From d9f2e8404bf30fa445142f63d1805e20a4d2f64c Mon Sep 17 00:00:00 2001
From: Emil Lerch <emil@lerch.org>
Date: Wed, 20 May 2026 15:20:44 -0700
Subject: [PATCH] allow tiingo to merge in dividends/splits not captured by
 primary provider

---
 README.md                |  51 ++---
 src/cache/store.zig      | 435 ++++++++++++++++++++++++++++++++++++++-
 src/providers/tiingo.zig | 349 +++++++++++++++++++++++++++----
 src/service.zig          | 100 +++++++--
 4 files changed, 848 insertions(+), 87 deletions(-)

diff --git a/README.md b/README.md
index eccb5a6..b75c2fe 100644
--- a/README.md
+++ b/README.md
@@ -45,30 +45,31 @@ zfin aggregates data from multiple free-tier APIs. Each provider is used for the
 
 ### Tiingo
 
-**Used for:** daily candles (primary provider for all symbols).
+**Used for:** daily candles (primary provider for all symbols), supplementary dividend and split data.
 
 - Endpoint: `https://api.tiingo.com/tiingo/daily/{symbol}/prices`
 - Free tier: 1,000 requests per day, no per-minute restriction.
 - Covers stocks, ETFs, and mutual funds. Mutual fund NAVs are available after midnight ET.
-- Candles are fetched with a 10-year + 60-day lookback window for trailing return calculations.
-- Returns split-adjusted prices with `adjClose` for dividend-adjusted values.
+- Candles are fetched with a fixed 2000-01-01 start date so the cache supports `--as-of` projections back to the earliest imported portfolio data (typically 2014) with full 10Y trailing-return windows.
+- The same response carries per-row `divCash` and `splitFactor`. We extract these as a free side benefit and merge them into the dividend/split caches alongside Polygon's primary view -- this rescues entries Polygon's reference endpoints miss (e.g. SPYM's 2017-10-16 4:1 split).
 
 ### TwelveData
 
-**Used for:** candle fallback (when Tiingo fails), real-time quotes (fallback after Yahoo).
+**Used for:** real-time quote fallback (after Yahoo).
 
-- Endpoint: `https://api.twelvedata.com/time_series` and `/quote`
-- Free tier: 8 API credits per minute, 800 per day. Each symbol in a request costs 1 credit.
-- Mutual fund NAV updates can lag by a full trading day compared to Tiingo.
+- Endpoint: `https://api.twelvedata.com/quote`
+- Free tier: 8 API credits per minute, 800 per day.
+- TwelveData was previously used for candles but is no longer in the candle pipeline -- its `adj_close` values were unreliable for split-adjustment math. Yahoo is the candle fallback now.
 
 ### Polygon
 
-**Used for:** dividend and stock splits information, both historical and upcoming.
+**Used for:** dividend and stock split data, both historical and forward-looking.
 
 - Endpoints: `https://api.polygon.io/v3/reference/dividends` and `/v3/reference/splits`
-- Free tier: 5 requests per minute, unlimited daily. Full historical dividend/split data.
+- Free tier: 5 requests per minute, unlimited daily. Full historical data.
 - Dividend endpoint uses cursor-based pagination (automatically followed).
-- Provides dividend type classification (regular, special, supplemental).
+- Provides dividend type classification (regular, special, supplemental) and richer metadata than Tiingo (`pay_date`, `record_date`, `currency`).
+- Polygon is **primary** for dividends and splits because it carries forward-looking declared events (e.g. ARCC's next ex-dividend date several months out) that Tiingo's price-series response cannot provide. Tiingo merges in supplementary entries for historical events Polygon's reference endpoints occasionally miss.
 
 ### CBOE
 
@@ -101,7 +102,7 @@ Set keys as environment variables or in a `.env` file (searched in the executabl
 
 ```bash
 TIINGO_API_KEY=your_key        # Required for candles (primary provider)
-TWELVEDATA_API_KEY=your_key    # Candle fallback, quote fallback
+TWELVEDATA_API_KEY=your_key    # Quote fallback (after Yahoo)
 POLYGON_API_KEY=your_key       # Required for dividends/splits (total returns)
 FMP_API_KEY=your_key           # Required for earnings data
 ALPHAVANTAGE_API_KEY=your_key  # Required for ETF profiles
@@ -111,13 +112,13 @@ The cache directory defaults to `~/.cache/zfin` and can be overridden with `ZFIN
 
 Not all keys are required. Without a key, the corresponding data simply won't be available:
 
-| Key                    | Without it                                                         |
-|------------------------|--------------------------------------------------------------------|
-| `TIINGO_API_KEY`       | Candles fall back to TwelveData, then Yahoo                        |
-| `TWELVEDATA_API_KEY`   | No candle fallback after Tiingo, no quote fallback after Yahoo     |
-| `POLYGON_API_KEY`      | No dividends -- trailing returns show price-only (no total return) |
-| `FMP_API_KEY`          | No earnings data (tab disabled)                                    |
-| `ALPHAVANTAGE_API_KEY` | No ETF profiles                                                    |
+| Key                    | Without it                                                                          |
+|------------------------|-------------------------------------------------------------------------------------|
+| `TIINGO_API_KEY`       | Candles fall back to Yahoo only; some symbols (especially mutual funds) won't work  |
+| `TWELVEDATA_API_KEY`   | No quote fallback after Yahoo                                                       |
+| `POLYGON_API_KEY`      | No forward-looking dividends; trailing total returns may use only Tiingo's view     |
+| `FMP_API_KEY`          | No earnings data (tab disabled)                                                     |
+| `ALPHAVANTAGE_API_KEY` | No ETF profiles                                                                     |
 
 CBOE options require no API key.
 
@@ -276,7 +277,7 @@ The TUI has eight tabs: Portfolio, Analysis, Projections, History, Quote, Perfor
 
 **Quote** -- current price, OHLCV, daily change, and a 60-day ASCII chart with recent history table.
 
-**Performance** -- trailing returns using two methodologies (as-of-date and month-end), matching Morningstar's "Trailing Returns" and "Performance" pages respectively. Shows price-only and total return (with dividend reinvestment) when Polygon data is available. Also shows risk metrics (volatility, Sharpe ratio, max drawdown).
+**Performance** -- trailing returns using two methodologies (as-of-date and month-end), matching Morningstar's "Trailing Returns" and "Performance" pages respectively. Shows price-only and total return (with dividend reinvestment) using whichever dividend data is available -- Polygon (richer metadata, forward-looking entries) and Tiingo (extracted from candle responses, historical only) are merged. Also shows risk metrics (volatility, Sharpe ratio, max drawdown).
 
 **Earnings** -- historical and upcoming earnings events with EPS estimate/actual, surprise amount and percentage. Future events are dimmed. Tab is disabled for ETFs.
 
@@ -415,7 +416,7 @@ security_type::watch,symbol::TSLA
 
 ### Security types
 
-- **stock** (default) -- Stocks, ETFs, and mutual funds. Prices are fetched from Tiingo (primary), TwelveData, or Yahoo (fallbacks). Positions are aggregated by symbol and shown with gain/loss.
+- **stock** (default) -- Stocks, ETFs, and mutual funds. Prices are fetched from Tiingo (primary) or Yahoo (candle fallback). Positions are aggregated by symbol and shown with gain/loss.
 - **option** -- Option contracts. Shown in a separate "Options" section. Shares can be negative for short positions.
 - **cd** -- Certificates of deposit. Shown sorted by maturity date with rate and face value.
 - **cash** -- Cash, money market, and settlement balances. Shown grouped by account with optional notes.
@@ -426,7 +427,7 @@ security_type::watch,symbol::TSLA
 
 For stock lots, prices are resolved in this order:
 
-1. **Live API** -- Latest close from cached candles (Tiingo/TwelveData/Yahoo)
+1. **Live API** -- Latest close from cached candles (Tiingo, with Yahoo as candle fallback)
 2. **Manual price** -- `price::` field on the lot (for securities without API coverage, e.g. 401k CIT share classes)
 3. **Average cost** -- Falls back to the position's `open_price` as a last resort
 
@@ -866,13 +867,13 @@ src/
     classification.zig  Classification metadata parser
     quote.zig           Real-time quote data
   providers/
-    tiingo.zig          Tiingo: daily candles (primary)
-    twelvedata.zig      TwelveData: candles (fallback), quotes (fallback)
-    polygon.zig         Polygon: dividends, splits
+    tiingo.zig          Tiingo: daily candles (primary), supplementary div/split merge
+    twelvedata.zig      TwelveData: quote fallback
+    polygon.zig         Polygon: dividends, splits (primary, with forward-looking entries)
     fmp.zig             FMP: earnings (actuals + estimates)
     cboe.zig            CBOE: options chains (no API key)
     alphavantage.zig    Alpha Vantage: ETF profiles, company overview
-    yahoo.zig           Yahoo Finance: quotes (primary), candles (last resort)
+    yahoo.zig           Yahoo Finance: quotes (primary), candles (Tiingo fallback)
     openfigi.zig        OpenFIGI: CUSIP to ticker lookup
   analytics/
     indicators.zig      SMA, Bollinger Bands, RSI
diff --git a/src/cache/store.zig b/src/cache/store.zig
index 545b9d8..d484922 100644
--- a/src/cache/store.zig
+++ b/src/cache/store.zig
@@ -196,6 +196,13 @@ pub const Store = struct {
 
     /// Serialize data and write to cache with the given TTL.
     /// Accepts a slice for most types, or a single struct for EtfProfile.
+    ///
+    /// For `Dividend` and `Split`, this dispatches to `writeMerged`,
+    /// which performs sorted-union-with-existing semantics rather than
+    /// a clean overwrite. Both Tiingo's full-history view and
+    /// Polygon's targeted fetches converge to the same on-disk union
+    /// regardless of write order, and forward-looking entries from
+    /// Polygon are preserved across Tiingo refreshes.
     pub fn write(
         self: *Store,
         comptime T: type,
@@ -203,6 +210,26 @@ pub const Store = struct {
         items: DataFor(T),
         ttl: i64,
     ) void {
+        self.writeWithSource(T, symbol, items, ttl, null);
+    }
+
+    /// Same as `write` but lets the caller attribute new entries to a
+    /// named source (e.g. `"tiingo"`). The source name appears in the
+    /// `info(cache)` log line emitted by `writeMerged` when a
+    /// previously-unseen dividend or split lands in the cache. For
+    /// types that don't go through the merge path, the hint is unused.
+    pub fn writeWithSource(
+        self: *Store,
+        comptime T: type,
+        symbol: []const u8,
+        items: DataFor(T),
+        ttl: i64,
+        source_hint: ?[]const u8,
+    ) void {
+        if (T == Dividend or T == Split) {
+            self.writeMerged(T, symbol, items, ttl, source_hint);
+            return;
+        }
         const expires = std.Io.Timestamp.now(self.io, .real).toSeconds() + ttl;
         const data_type = dataTypeFor(T);
         if (T == EtfProfile) {
@@ -237,6 +264,117 @@ pub const Store = struct {
         };
     }
 
+    /// Sorted-union write for `Dividend` and `Split`. Reads the
+    /// existing cache file, adds any items from `incoming` whose
+    /// date key isn't already present, sorts the union descending
+    /// by date, and writes the result. If nothing new came in, the
+    /// existing file is left untouched (no mtime bump, no I/O).
+    ///
+    /// Existing entries always win on key collision: Polygon's
+    /// dividend records carry richer metadata (`pay_date`,
+    /// `record_date`, `type`, `currency`) than Tiingo's, so once
+    /// Polygon has supplied an ex_date we don't want a later Tiingo
+    /// write to overwrite it with a sparser record. The merge
+    /// preserves whichever entry landed first for any given date.
+    ///
+    /// Each newly-added entry triggers an `info(cache)` log line so
+    /// the user is alerted when a supplementary source (Tiingo,
+    /// usually) discovers a corporate action the primary source
+    /// (Polygon) missed. The `source_hint` argument, when present,
+    /// names the source in that log line.
+    fn writeMerged(
+        self: *Store,
+        comptime T: type,
+        symbol: []const u8,
+        incoming: []const T,
+        ttl: i64,
+        source_hint: ?[]const u8,
+    ) void {
+        comptime std.debug.assert(T == Dividend or T == Split);
+
+        // Read existing entries (any freshness; we want the union of
+        // what's on disk, not just fresh data).
+        const existing_result = self.read(T, symbol, null, .any);
+        const existing: []const T = if (existing_result) |r| r.data else &.{};
+        defer if (existing_result != null) {
+            if (comptime @hasDecl(T, "deinit")) {
+                for (existing) |item| item.deinit(self.allocator);
+            }
+            self.allocator.free(existing);
+        };
+
+        // Build the union. Start with existing entries, then append
+        // any incoming entry whose key isn't already present.
+        var merged: std.ArrayList(T) = .empty;
+        defer merged.deinit(self.allocator);
+        merged.appendSlice(self.allocator, existing) catch return;
+
+        var added: usize = 0;
+        for (incoming) |item| {
+            if (containsKey(T, merged.items, mergeKey(T, item))) continue;
+            merged.append(self.allocator, item) catch return;
+            added += 1;
+            logSupplied(T, symbol, item, source_hint);
+        }
+
+        if (added == 0) {
+            // Nothing new — leave the file untouched. This is the
+            // common case for repeated Polygon/Tiingo refreshes.
+            return;
+        }
+
+        // Sort descending by date (newest first), matching the
+        // existing on-disk convention.
+        std.mem.sort(T, merged.items, {}, lessByDateDesc(T));
+
+        // Serialize via the same generic path as `write` for
+        // non-merged types, but write the union we just built.
+        const expires = std.Io.Timestamp.now(self.io, .real).toSeconds() + ttl;
+        const data_type = dataTypeFor(T);
+        const srf_data = serializeWithMeta(T, self.io, self.allocator, merged.items, .{ .expires = expires }) catch |err| {
+            log.warn("{s}: failed to serialize {s}: {s}", .{ symbol, @tagName(data_type), @errorName(err) });
+            return;
+        };
+        defer self.allocator.free(srf_data);
+        self.writeRaw(symbol, data_type, srf_data) catch |err| {
+            log.warn("{s}: failed to write {s} to cache: {s}", .{ symbol, @tagName(data_type), @errorName(err) });
+        };
+    }
+
+    fn mergeKey(comptime T: type, item: T) i32 {
+        if (T == Dividend) return item.ex_date.days;
+        if (T == Split) return item.date.days;
+        @compileError("mergeKey only defined for Dividend and Split");
+    }
+
+    fn containsKey(comptime T: type, items: []const T, key: i32) bool {
+        for (items) |it| {
+            if (mergeKey(T, it) == key) return true;
+        }
+        return false;
+    }
+
+    fn lessByDateDesc(comptime T: type) fn (void, T, T) bool {
+        return struct {
+            fn lt(_: void, a: T, b: T) bool {
+                return mergeKey(T, a) > mergeKey(T, b);
+            }
+        }.lt;
+    }
+
+    fn logSupplied(comptime T: type, symbol: []const u8, item: T, source_hint: ?[]const u8) void {
+        const source = source_hint orelse "fetch";
+        if (T == Dividend) {
+            log.info("{s}: {s} supplied dividend ex_date {f} amount ${d:.4}", .{
+                symbol, source, item.ex_date, item.amount,
+            });
+        } else if (T == Split) {
+            log.info("{s}: {s} supplied split {f} {d}:{d}", .{
+                symbol, source, item.date, @as(u64, @intFromFloat(item.numerator)), @as(u64, @intFromFloat(item.denominator)),
+            });
+        }
+    }
+
     // ── Candle-specific API ──────────────────────────────────────
 
     /// Write a full set of candles to cache (no expiry — historical facts don't expire).
@@ -673,9 +811,23 @@ pub const Store = struct {
     pub const CandleMeta = struct {
         last_close: f64,
         last_date: Date,
-        /// Which provider sourced the candle data. Used during incremental refresh
-        /// to go directly to the right provider instead of trying Tiingo first.
-        provider: CandleProvider = .tiingo,
+        /// Which provider sourced the candle data. **No default
+        /// value on purpose** — SRF auto-elides fields whose value
+        /// equals their default, which would hide the provider line
+        /// when it equaled the implicit default. We want every cache
+        /// file to record its provider explicitly so cache inspection
+        /// can always answer "where did this come from?". Construction
+        /// sites must pass the provider explicitly.
+        ///
+        /// Cache compatibility: pre-2026-05 caches that elided the
+        /// provider field will fail to deserialize after this change
+        /// (SRF returns FieldNotFoundOnFieldWithoutDefaultValue).
+        /// `readCandleMeta` swallows the error and returns null,
+        /// making the symbol look like a cache miss — `getCandles`
+        /// then triggers a fresh fetch via `populateAllFromTiingo`,
+        /// which writes a new meta file with the provider explicit.
+        /// The wipe happens naturally on first use post-upgrade.
+        provider: CandleProvider,
         /// Consecutive transient failure count for the primary provider (Tiingo).
         /// Incremented on ServerError; reset to 0 on success. When >= 3, the
         /// symbol is degraded to a fallback provider until Tiingo recovers.
@@ -683,8 +835,21 @@ pub const Store = struct {
     };
 
     pub const CandleProvider = enum {
+        /// Legacy: candles were sourced from TwelveData. No new
+        /// writes produce this value (TwelveData was demoted in an
+        /// earlier change because its `adj_close` was unreliable).
+        /// Cache reads still recognize the value for backwards
+        /// compatibility.
         twelvedata,
+        /// Legacy: candles were sourced from Yahoo Finance. No new
+        /// writes produce this value (Yahoo was removed from the
+        /// candle pipeline in the 2026-05 audit; Yahoo is still used
+        /// for `getQuote` real-time prices but not for historical
+        /// candles). Cache reads still recognize the value for
+        /// backwards compatibility.
         yahoo,
+        /// Active: candles sourced from Tiingo. The only value
+        /// produced by current writes.
         tiingo,
 
         pub fn fromString(s: []const u8) CandleProvider {
@@ -851,6 +1016,11 @@ pub const Store = struct {
         return aw.toOwnedSlice();
     }
 
+    /// Serialize CandleMeta to its SRF on-disk representation.
+    /// Uses SRF's generic field emission. Because `CandleMeta`
+    /// declares no default for `provider`, every meta file emits
+    /// the provider line explicitly — cache inspection can always
+    /// answer "where did this come from?".
     fn serializeCandleMeta(io: std.Io, allocator: std.mem.Allocator, meta: CandleMeta, options: srf.FormatOptions) ![]const u8 {
         var aw: std.Io.Writer.Allocating = .init(allocator);
         errdefer aw.deinit();
@@ -1186,6 +1356,195 @@ test "split serialize/deserialize round-trip" {
     try std.testing.expectApproxEqAbs(@as(f64, 7), parsed[1].numerator, 0.001);
 }
 
+test "writeMerged Dividend: empty cache writes input sorted descending" {
+    const allocator = std.testing.allocator;
+    const io = std.testing.io;
+    var tmp = std.testing.tmpDir(.{});
+    defer tmp.cleanup();
+    const dir_path = try tmp.dir.realPathFileAlloc(io, ".", allocator);
+    defer allocator.free(dir_path);
+
+    var s = Store.init(io, allocator, dir_path);
+    // Intentionally pass entries out of order — writeMerged must sort.
+    var incoming = [_]Dividend{
+        .{ .ex_date = Date.fromYmd(2024, 5, 15), .amount = 0.50 },
+        .{ .ex_date = Date.fromYmd(2024, 8, 15), .amount = 0.55 },
+        .{ .ex_date = Date.fromYmd(2024, 2, 15), .amount = 0.48 },
+    };
+    s.write(Dividend, "TEST", incoming[0..], Ttl.dividends);
+
+    const result = s.read(Dividend, "TEST", null, .any) orelse return error.NoCache;
+    defer allocator.free(result.data);
+    defer for (result.data) |d| d.deinit(allocator);
+
+    try std.testing.expectEqual(@as(usize, 3), result.data.len);
+    try std.testing.expect(result.data[0].ex_date.eql(Date.fromYmd(2024, 8, 15)));
+    try std.testing.expect(result.data[1].ex_date.eql(Date.fromYmd(2024, 5, 15)));
+    try std.testing.expect(result.data[2].ex_date.eql(Date.fromYmd(2024, 2, 15)));
+}
+
+test "writeMerged Dividend: existing entries preserved on key collision" {
+    const allocator = std.testing.allocator;
+    const io = std.testing.io;
+    var tmp = std.testing.tmpDir(.{});
+    defer tmp.cleanup();
+    const dir_path = try tmp.dir.realPathFileAlloc(io, ".", allocator);
+    defer allocator.free(dir_path);
+
+    var s = Store.init(io, allocator, dir_path);
+    // Initial write: rich entry from "Polygon" with metadata.
+    var initial = [_]Dividend{
+        .{
+            .ex_date = Date.fromYmd(2024, 5, 15),
+            .pay_date = Date.fromYmd(2024, 6, 1),
+            .amount = 0.50,
+            .type = .regular,
+        },
+    };
+    s.write(Dividend, "TEST", initial[0..], Ttl.dividends);
+
+    // Second write: same ex_date, sparser entry (Tiingo-style: no pay_date, no type).
+    // Existing entry should win.
+    var incoming = [_]Dividend{
+        .{ .ex_date = Date.fromYmd(2024, 5, 15), .amount = 0.99, .type = .unknown },
+    };
+    s.write(Dividend, "TEST", incoming[0..], Ttl.dividends);
+
+    const result = s.read(Dividend, "TEST", null, .any) orelse return error.NoCache;
+    defer allocator.free(result.data);
+    defer for (result.data) |d| d.deinit(allocator);
+
+    try std.testing.expectEqual(@as(usize, 1), result.data.len);
+    // Original Polygon-style amount (0.50) must remain — Tiingo's 0.99 must not overwrite.
+    try std.testing.expectApproxEqAbs(@as(f64, 0.50), result.data[0].amount, 0.001);
+    try std.testing.expect(result.data[0].pay_date != null);
+    try std.testing.expectEqual(DividendType.regular, result.data[0].type);
+}
+
+test "writeMerged Dividend: union sorted desc, new entry added" {
+    const allocator = std.testing.allocator;
+    const io = std.testing.io;
+    var tmp = std.testing.tmpDir(.{});
+    defer tmp.cleanup();
+    const dir_path = try tmp.dir.realPathFileAlloc(io, ".", allocator);
+    defer allocator.free(dir_path);
+
+    var s = Store.init(io, allocator, dir_path);
+    var initial = [_]Dividend{
+        .{ .ex_date = Date.fromYmd(2024, 5, 15), .amount = 0.50, .type = .regular },
+        .{ .ex_date = Date.fromYmd(2024, 2, 15), .amount = 0.48, .type = .regular },
+    };
+    s.write(Dividend, "TEST", initial[0..], Ttl.dividends);
+
+    // New ex_date that wasn't already present.
+    var incoming = [_]Dividend{
+        .{ .ex_date = Date.fromYmd(2024, 8, 15), .amount = 0.55 },
+    };
+    s.write(Dividend, "TEST", incoming[0..], Ttl.dividends);
+
+    const result = s.read(Dividend, "TEST", null, .any) orelse return error.NoCache;
+    defer allocator.free(result.data);
+    defer for (result.data) |d| d.deinit(allocator);
+
+    try std.testing.expectEqual(@as(usize, 3), result.data.len);
+    try std.testing.expect(result.data[0].ex_date.eql(Date.fromYmd(2024, 8, 15)));
+    try std.testing.expect(result.data[1].ex_date.eql(Date.fromYmd(2024, 5, 15)));
+    try std.testing.expect(result.data[2].ex_date.eql(Date.fromYmd(2024, 2, 15)));
+}
+
+test "writeMerged Dividend: no-op when nothing new" {
+    const allocator = std.testing.allocator;
+    const io = std.testing.io;
+    var tmp = std.testing.tmpDir(.{});
+    defer tmp.cleanup();
+    const dir_path = try tmp.dir.realPathFileAlloc(io, ".", allocator);
+    defer allocator.free(dir_path);
+
+    var s = Store.init(io, allocator, dir_path);
+    var initial = [_]Dividend{
+        .{ .ex_date = Date.fromYmd(2024, 5, 15), .amount = 0.50, .type = .regular },
+    };
+    s.write(Dividend, "TEST", initial[0..], Ttl.dividends);
+
+    // Capture file mtime before second (no-op) write.
+    const path = try std.fs.path.join(allocator, &.{ dir_path, "TEST", "dividends.srf" });
+    defer allocator.free(path);
+    const stat_before = try std.Io.Dir.cwd().statFile(io, path, .{});
+
+    // Sleep briefly so mtime resolution can detect a write if one happens.
+    std.Io.sleep(io, std.Io.Duration.fromMilliseconds(20), .awake) catch {};
+
+    // Same incoming entry — nothing new, should not rewrite.
+    var repeat = [_]Dividend{
+        .{ .ex_date = Date.fromYmd(2024, 5, 15), .amount = 0.50, .type = .regular },
+    };
+    s.write(Dividend, "TEST", repeat[0..], Ttl.dividends);
+
+    const stat_after = try std.Io.Dir.cwd().statFile(io, path, .{});
+    try std.testing.expectEqual(stat_before.mtime, stat_after.mtime);
+}
+
+test "writeMerged Split: SPYM-style supplementary entry added" {
+    const allocator = std.testing.allocator;
+    const io = std.testing.io;
+    var tmp = std.testing.tmpDir(.{});
+    defer tmp.cleanup();
+    const dir_path = try tmp.dir.realPathFileAlloc(io, ".", allocator);
+    defer allocator.free(dir_path);
+
+    var s = Store.init(io, allocator, dir_path);
+    // Polygon's view: empty (the bug case — Polygon doesn't carry SPYM's 2017 split).
+    var initial = [_]Split{};
+    s.write(Split, "SPYM", initial[0..], Ttl.splits);
+
+    // Tiingo supplements with the 2017 4:1 split.
+    var tiingo_view = [_]Split{
+        .{ .date = Date.fromYmd(2017, 10, 16), .numerator = 4, .denominator = 1 },
+    };
+    s.write(Split, "SPYM", tiingo_view[0..], Ttl.splits);
+
+    const result = s.read(Split, "SPYM", null, .any) orelse return error.NoCache;
+    defer allocator.free(result.data);
+
+    try std.testing.expectEqual(@as(usize, 1), result.data.len);
+    try std.testing.expect(result.data[0].date.eql(Date.fromYmd(2017, 10, 16)));
+    try std.testing.expectApproxEqAbs(@as(f64, 4), result.data[0].numerator, 0.001);
+}
+
+test "writeMerged Split: forward-looking Polygon entry preserved across Tiingo refresh" {
+    // Simulates the ARCC-like case for splits: Polygon writes a
+    // forward-looking entry; a later Tiingo write must not erase it.
+    const allocator = std.testing.allocator;
+    const io = std.testing.io;
+    var tmp = std.testing.tmpDir(.{});
+    defer tmp.cleanup();
+    const dir_path = try tmp.dir.realPathFileAlloc(io, ".", allocator);
+    defer allocator.free(dir_path);
+
+    var s = Store.init(io, allocator, dir_path);
+    // Polygon initial: includes a forward-looking entry.
+    var polygon_view = [_]Split{
+        .{ .date = Date.fromYmd(2026, 12, 1), .numerator = 2, .denominator = 1 },
+        .{ .date = Date.fromYmd(2020, 8, 31), .numerator = 4, .denominator = 1 },
+    };
+    s.write(Split, "TEST", polygon_view[0..], Ttl.splits);
+
+    // Tiingo refresh: only knows about historical entries (its own data
+    // doesn't include forward-looking yet-to-occur splits).
+    var tiingo_view = [_]Split{
+        .{ .date = Date.fromYmd(2020, 8, 31), .numerator = 4, .denominator = 1 },
+    };
+    s.write(Split, "TEST", tiingo_view[0..], Ttl.splits);
+
+    const result = s.read(Split, "TEST", null, .any) orelse return error.NoCache;
+    defer allocator.free(result.data);
+
+    // Both entries must remain — Polygon's forward-looking entry survives.
+    try std.testing.expectEqual(@as(usize, 2), result.data.len);
+    try std.testing.expect(result.data[0].date.eql(Date.fromYmd(2026, 12, 1)));
+    try std.testing.expect(result.data[1].date.eql(Date.fromYmd(2020, 8, 31)));
+}
+
 test "portfolio serialize/deserialize round-trip" {
     const allocator = std.testing.allocator;
     // Today is after the lots' open_dates and after the one close_date,
@@ -1592,14 +1951,82 @@ test "Store init creates valid store" {
     try std.testing.expectEqualStrings("/tmp/zfin-test", store.cache_dir);
 }
 
-test "CandleMeta default provider is tiingo" {
+test "CandleMeta has no default provider (must be set explicitly)" {
+    // Regression: pre-2026-05 the model had `provider: CandleProvider = .tiingo`
+    // which caused SRF to elide the field when it equaled the default,
+    // hiding the provider in cache inspection. We removed the default
+    // so every cache file records its provider explicitly.
+    //
+    // This test confirms the field is required at construction. If
+    // someone re-adds a default later, this test fails to compile.
     const meta = Store.CandleMeta{
         .last_close = 100.0,
         .last_date = Date.fromYmd(2024, 1, 1),
+        .provider = .tiingo,
     };
     try std.testing.expectEqual(Store.CandleProvider.tiingo, meta.provider);
 }
 
+test "serializeCandleMeta unconditionally emits provider field" {
+    // Regression: SRF auto-elision used to hide `provider::tiingo`
+    // when it equaled the model default. With the default removed
+    // from the struct, SRF emits the field unconditionally.
+    const allocator = std.testing.allocator;
+    const meta = Store.CandleMeta{
+        .last_close = 100.0,
+        .last_date = Date.fromYmd(2024, 1, 1),
+        .provider = .tiingo,
+    };
+    const data = try Store.serializeCandleMeta(std.testing.io, allocator, meta, .{ .expires = 1234567890 });
+    defer allocator.free(data);
+
+    try std.testing.expect(std.mem.indexOf(u8, data, "provider::tiingo") != null);
+    try std.testing.expect(std.mem.indexOf(u8, data, "last_close:num:100") != null);
+    try std.testing.expect(std.mem.indexOf(u8, data, "last_date::2024-01-01") != null);
+    try std.testing.expect(std.mem.indexOf(u8, data, "#!expires=1234567890") != null);
+}
+
+test "serializeCandleMeta round-trips through deserializeCandleMeta" {
+    const allocator = std.testing.allocator;
+    const meta = Store.CandleMeta{
+        .last_close = 42.57,
+        .last_date = Date.fromYmd(2026, 5, 19),
+        .provider = .tiingo,
+        .fail_count = 2,
+    };
+    const data = try Store.serializeCandleMeta(std.testing.io, allocator, meta, .{ .expires = 1234567890 });
+    defer allocator.free(data);
+
+    const parsed = try Store.deserializeCandleMeta(allocator, data);
+    try std.testing.expectApproxEqAbs(@as(f64, 42.57), parsed.last_close, 0.001);
+    try std.testing.expect(parsed.last_date.eql(Date.fromYmd(2026, 5, 19)));
+    try std.testing.expectEqual(Store.CandleProvider.tiingo, parsed.provider);
+    try std.testing.expectEqual(@as(u8, 2), parsed.fail_count);
+}
+
+test "deserializeCandleMeta fails on old cache that elided provider field" {
+    // Pre-2026-05 cache files elided `provider::tiingo` when it
+    // equaled the model default. Those caches no longer deserialize
+    // (model has no default for provider). The graceful handling is
+    // upstream: `readCandleMeta` swallows the deserialization error
+    // and returns null, which makes `getCandles` treat it as a cache
+    // miss and trigger a fresh fetch via `populateAllFromTiingo`.
+    // The new fetch writes a meta file with the provider explicit.
+    //
+    // This test documents the failure mode and confirms it's not a
+    // silent corruption — the caller gets an error, not stale data.
+    const allocator = std.testing.allocator;
+    const old_format =
+        \\#!srfv1
+        \\#!expires=1779384748
+        \\#!created=1779299248
+        \\last_close:num:298.97,last_date::2026-05-19
+        \\
+    ;
+    const result = Store.deserializeCandleMeta(allocator, old_format);
+    try std.testing.expectError(error.InvalidData, result);
+}
+
 // ── writeRaw / appendRaw atomicity ───────────────────────────
 //
 // A concurrent reader hitting a cache file mid-write must never see a
diff --git a/src/providers/tiingo.zig b/src/providers/tiingo.zig
index 3be083a..32c821c 100644
--- a/src/providers/tiingo.zig
+++ b/src/providers/tiingo.zig
@@ -1,21 +1,71 @@
-//! Tiingo provider -- official REST API for end-of-day prices.
+//! Tiingo provider -- official REST API for end-of-day prices and corporate actions.
 //!
 //! Free tier: 1,000 requests/day, no per-minute restriction.
 //! Covers stocks, ETFs, and mutual funds with same-day NAV updates
 //! (mutual fund NAVs available after midnight ET).
 //!
 //! API docs: https://www.tiingo.com/documentation/end-of-day
+//!
+//! ## Role in the data pipeline
+//!
+//! Tiingo is the **primary candle provider**. Yahoo is the fallback
+//! when Tiingo can't serve a symbol. Tiingo's `/daily/<sym>/prices`
+//! response also carries per-row `divCash` and `splitFactor`, which
+//! we extract during candle parsing as a free side benefit — the
+//! candle, dividend, and split data all come from a single HTTP call.
+//!
+//! For dividends and splits the **primary source is Polygon**, not
+//! Tiingo. Polygon's dedicated corporate-actions endpoints carry
+//! forward-looking declared events (e.g. ARCC's next ex-dividend
+//! date several months out) that Tiingo's price-series response
+//! cannot provide — Tiingo only reports events that have already
+//! affected a price bar. Polygon also carries richer metadata per
+//! dividend (`pay_date`, `record_date`, `type`, `currency`).
+//!
+//! Tiingo's dividend/split contribution is **supplementary**. The
+//! `populateAllFromTiingo` orchestration in `service.zig` writes
+//! Tiingo's view through `cache.Store.writeWithSource(..., "tiingo")`,
+//! which dispatches to the sorted-union merge primitive. Polygon's
+//! existing entries in `dividends.srf` / `splits.srf` are preserved
+//! on key collision; Tiingo entries that name new ex_dates / split
+//! dates are merged in and logged at `info(cache)` level.
+//!
+//! The canonical case where Tiingo's supplementary view rescues the
+//! cache is SPYM's 2017-10-16 4:1 split — present in Tiingo's
+//! historical bars but absent from Polygon's splits endpoint. Without
+//! the merge, SPYM's 10Y price-only return would be off by ~14pp.
+//!
+//! ## Tiingo dividend records carry less metadata
+//!
+//! Tiingo only emits `divCash` (the cash amount) per dividend event.
+//! When Tiingo merges a previously-unseen ex_date into the cache,
+//! `pay_date`, `record_date`, `type`, and `currency` will be `null`
+//! / `.unknown`. The total-return calculation only needs `ex_date`
+//! and `amount`, both of which Tiingo provides; `divs.zig`
+//! gracefully handles missing display fields.
 
 const std = @import("std");
 const http = @import("../net/http.zig");
 const Date = @import("../Date.zig");
 const Candle = @import("../models/candle.zig").Candle;
+const Dividend = @import("../models/dividend.zig").Dividend;
+const Split = @import("../models/split.zig").Split;
 const json_utils = @import("json_utils.zig");
 const optFloat = json_utils.optFloat;
 const jsonStr = json_utils.jsonStr;
 
 const base_url = "https://api.tiingo.com/tiingo/daily";
 
+/// Combined fetch result: candles, dividends, and splits parsed from
+/// a single `/daily/<sym>/prices` response. Caller owns all three
+/// slices and must free them (and `Dividend.deinit` each entry for
+/// the currency string).
+pub const CandleAndCorporateActions = struct {
+    candles: []Candle,
+    dividends: []Dividend,
+    splits: []Split,
+};
+
 pub const Tiingo = struct {
     client: http.Client,
     allocator: std.mem.Allocator,
@@ -33,15 +83,17 @@ pub const Tiingo = struct {
         self.client.deinit();
     }
 
-    /// Fetch daily candles for a symbol between two dates (inclusive).
-    /// Returns candles sorted oldest-first.
-    pub fn fetchCandles(
+    /// Fetch candles, dividends, and splits in one HTTP call. This is
+    /// the primary provider entry point — the three convenience
+    /// methods below all call this and free the slices they don't
+    /// need.
+    pub fn fetchCandlesAndCorporateActions(
         self: *Tiingo,
         allocator: std.mem.Allocator,
         symbol: []const u8,
         from: Date,
         to: Date,
-    ) ![]Candle {
+    ) !CandleAndCorporateActions {
         var from_buf: [10]u8 = undefined;
         var to_buf: [10]u8 = undefined;
         const from_str = std.fmt.bufPrint(&from_buf, "{f}", .{from}) catch unreachable;
@@ -60,13 +112,59 @@ pub const Tiingo = struct {
         var response = try self.client.get(url);
         defer response.deinit();
 
-        return parseCandles(allocator, response.body);
+        return parseAll(allocator, response.body);
+    }
+
+    /// Fetch daily candles for a symbol between two dates (inclusive).
+    /// Convenience wrapper around `fetchCandlesAndCorporateActions`
+    /// for callers that only want the candle slice.
+    pub fn fetchCandles(
+        self: *Tiingo,
+        allocator: std.mem.Allocator,
+        symbol: []const u8,
+        from: Date,
+        to: Date,
+    ) ![]Candle {
+        const triple = try self.fetchCandlesAndCorporateActions(allocator, symbol, from, to);
+        Dividend.freeSlice(allocator, triple.dividends);
+        allocator.free(triple.splits);
+        return triple.candles;
+    }
+
+    /// Fetch dividends for a symbol between two dates (inclusive).
+    /// Convenience wrapper around `fetchCandlesAndCorporateActions`.
+    pub fn fetchDividends(
+        self: *Tiingo,
+        allocator: std.mem.Allocator,
+        symbol: []const u8,
+        from: Date,
+        to: Date,
+    ) ![]Dividend {
+        const triple = try self.fetchCandlesAndCorporateActions(allocator, symbol, from, to);
+        allocator.free(triple.candles);
+        allocator.free(triple.splits);
+        return triple.dividends;
+    }
+
+    /// Fetch splits for a symbol between two dates (inclusive).
+    /// Convenience wrapper around `fetchCandlesAndCorporateActions`.
+    pub fn fetchSplits(
+        self: *Tiingo,
+        allocator: std.mem.Allocator,
+        symbol: []const u8,
+        from: Date,
+        to: Date,
+    ) ![]Split {
+        const triple = try self.fetchCandlesAndCorporateActions(allocator, symbol, from, to);
+        allocator.free(triple.candles);
+        Dividend.freeSlice(allocator, triple.dividends);
+        return triple.splits;
     }
 };
 
-/// Parse Tiingo's JSON array of price objects into Candles.
-/// Tiingo returns oldest-first, which matches our convention.
-fn parseCandles(allocator: std.mem.Allocator, body: []const u8) ![]Candle {
+/// Walk Tiingo's JSON array of price rows once, emitting candles,
+/// dividends (where `divCash != 0`), and splits (where `splitFactor != 1`).
+fn parseAll(allocator: std.mem.Allocator, body: []const u8) !CandleAndCorporateActions {
     const parsed = std.json.parseFromSlice(std.json.Value, allocator, body, .{}) catch
         return error.ParseError;
     defer parsed.deinit();
@@ -78,10 +176,17 @@ fn parseCandles(allocator: std.mem.Allocator, body: []const u8) ![]Candle {
     };
 
     var candles: std.ArrayList(Candle) = .empty;
+    errdefer candles.deinit(allocator);
+
+    var dividends: std.ArrayList(Dividend) = .empty;
     errdefer {
-        candles.deinit(allocator);
+        for (dividends.items) |d| d.deinit(allocator);
+        dividends.deinit(allocator);
     }
 
+    var splits: std.ArrayList(Split) = .empty;
+    errdefer splits.deinit(allocator);
+
     for (items) |item| {
         const obj = switch (item) {
             .object => |o| o,
@@ -103,9 +208,40 @@ fn parseCandles(allocator: std.mem.Allocator, body: []const u8) ![]Candle {
                 break :blk @intFromFloat(@max(0, v));
             },
         });
+
+        // Dividend event on this row (if any)
+        const div_cash = optFloat(obj.get("divCash")) orelse 0;
+        if (div_cash != 0) {
+            try dividends.append(allocator, .{
+                .ex_date = date,
+                .amount = div_cash,
+                // Tiingo doesn't carry pay_date / record_date /
+                // frequency / type. Display-only fields stay null /
+                // .unknown; total-return math only needs ex_date and
+                // amount.
+            });
+        }
+
+        // Split event on this row (if any). Tiingo represents a 4:1
+        // split as splitFactor = 4.0 and a 1:10 reverse split as
+        // splitFactor = 0.1. Both shapes are stored as
+        // numerator=splitFactor, denominator=1.0; `Split.ratio()`
+        // returns splitFactor in either case.
+        const split_factor = optFloat(obj.get("splitFactor")) orelse 1.0;
+        if (split_factor != 1.0 and split_factor != 0) {
+            try splits.append(allocator, .{
+                .date = date,
+                .numerator = split_factor,
+                .denominator = 1.0,
+            });
+        }
     }
 
-    return candles.toOwnedSlice(allocator);
+    return .{
+        .candles = try candles.toOwnedSlice(allocator),
+        .dividends = try dividends.toOwnedSlice(allocator),
+        .splits = try splits.toOwnedSlice(allocator),
+    };
 }
 
 /// Parse a Tiingo date string (e.g. "2026-03-16T00:00:00.000Z") into a Date.
@@ -117,7 +253,7 @@ fn parseDate(val: ?std.json.Value) ?Date {
 
 // -- Tests --
 
-test "parseCandles basic" {
+test "parseAll basic candles, no events" {
     const body =
         \\[
         \\  {
@@ -138,61 +274,188 @@ test "parseCandles basic" {
     ;
 
     const allocator = std.testing.allocator;
-    const candles = try parseCandles(allocator, body);
-    defer allocator.free(candles);
+    const triple = try parseAll(allocator, body);
+    defer allocator.free(triple.candles);
+    defer Dividend.freeSlice(allocator, triple.dividends);
+    defer allocator.free(triple.splits);
 
-    try std.testing.expectEqual(@as(usize, 2), candles.len);
+    try std.testing.expectEqual(@as(usize, 2), triple.candles.len);
+    try std.testing.expectEqual(@as(usize, 0), triple.dividends.len);
+    try std.testing.expectEqual(@as(usize, 0), triple.splits.len);
 
-    // Oldest first
-    try std.testing.expectEqual(@as(i16, 2026), candles[0].date.year());
-    try std.testing.expectEqual(@as(u8, 3), candles[0].date.month());
-    try std.testing.expectEqual(@as(u8, 13), candles[0].date.day());
-    try std.testing.expectApproxEqAbs(@as(f64, 42.41), candles[0].close, 0.01);
-
-    try std.testing.expectEqual(@as(u8, 16), candles[1].date.day());
-    try std.testing.expectApproxEqAbs(@as(f64, 42.74), candles[1].close, 0.01);
-    try std.testing.expectApproxEqAbs(@as(f64, 42.74), candles[1].adj_close, 0.01);
+    try std.testing.expectEqual(@as(i16, 2026), triple.candles[0].date.year());
+    try std.testing.expectApproxEqAbs(@as(f64, 42.41), triple.candles[0].close, 0.01);
+    try std.testing.expectApproxEqAbs(@as(f64, 42.74), triple.candles[1].close, 0.01);
 }
 
-test "parseCandles stock with volume" {
+test "parseAll extracts a dividend from a divCash row" {
+    // NKE 2024-03-01 dividend of $0.37 (real Tiingo response shape)
     const body =
         \\[
         \\  {
-        \\    "date": "2026-03-16T00:00:00.000Z",
-        \\    "close": 183.22, "high": 185.10, "low": 180.50, "open": 181.00,
-        \\    "volume": 217307380, "adjClose": 183.22, "adjHigh": 185.10,
-        \\    "adjLow": 180.50, "adjOpen": 181.00, "adjVolume": 217307380,
+        \\    "date": "2024-03-01T00:00:00.000Z",
+        \\    "close": 101.88, "high": 103.94, "low": 101.83, "open": 103.87,
+        \\    "volume": 7349270, "adjClose": 97.5550917628,
+        \\    "divCash": 0.37, "splitFactor": 1.0
+        \\  }
+        \\]
+    ;
+
+    const allocator = std.testing.allocator;
+    const triple = try parseAll(allocator, body);
+    defer allocator.free(triple.candles);
+    defer Dividend.freeSlice(allocator, triple.dividends);
+    defer allocator.free(triple.splits);
+
+    try std.testing.expectEqual(@as(usize, 1), triple.candles.len);
+    try std.testing.expectEqual(@as(usize, 1), triple.dividends.len);
+    try std.testing.expectEqual(@as(usize, 0), triple.splits.len);
+
+    const div = triple.dividends[0];
+    try std.testing.expect(div.ex_date.eql(Date.fromYmd(2024, 3, 1)));
+    try std.testing.expectApproxEqAbs(@as(f64, 0.37), div.amount, 0.001);
+    // Metadata fields are absent for Tiingo-sourced dividends
+    try std.testing.expect(div.pay_date == null);
+    try std.testing.expect(div.record_date == null);
+    try std.testing.expect(div.frequency == null);
+    try std.testing.expectEqual(@import("../models/dividend.zig").DividendType.unknown, div.type);
+}
+
+test "parseAll extracts forward 4:1 split (SPYM 2017 fixture)" {
+    // SPYM's actual 2017-10-16 split — verbatim Tiingo response shape.
+    // Polygon and FMP both miss this split; Tiingo has it via
+    // splitFactor: 4.0.
+    const body =
+        \\[
+        \\  {
+        \\    "date": "2017-10-13T00:00:00.000Z",
+        \\    "close": 119.7493, "open": 119.7667, "high": 120.26, "low": 119.7396,
+        \\    "volume": 7638, "adjClose": 26.0674934371,
+        \\    "divCash": 0.0, "splitFactor": 1.0
+        \\  },
+        \\  {
+        \\    "date": "2017-10-16T00:00:00.000Z",
+        \\    "close": 29.9556, "open": 30.01, "high": 30.01, "low": 29.9399,
+        \\    "volume": 8804, "adjClose": 26.0834061294,
+        \\    "divCash": 0.0, "splitFactor": 4.0
+        \\  },
+        \\  {
+        \\    "date": "2017-10-17T00:00:00.000Z",
+        \\    "close": 29.92, "open": 29.95, "high": 30.05, "low": 29.92,
+        \\    "volume": 21456, "adjClose": 26.0524079435,
         \\    "divCash": 0.0, "splitFactor": 1.0
         \\  }
         \\]
     ;
 
     const allocator = std.testing.allocator;
-    const candles = try parseCandles(allocator, body);
-    defer allocator.free(candles);
+    const triple = try parseAll(allocator, body);
+    defer allocator.free(triple.candles);
+    defer Dividend.freeSlice(allocator, triple.dividends);
+    defer allocator.free(triple.splits);
 
-    try std.testing.expectEqual(@as(usize, 1), candles.len);
-    try std.testing.expectApproxEqAbs(@as(f64, 181.00), candles[0].open, 0.01);
-    try std.testing.expectApproxEqAbs(@as(f64, 185.10), candles[0].high, 0.01);
-    try std.testing.expectApproxEqAbs(@as(f64, 180.50), candles[0].low, 0.01);
-    try std.testing.expectApproxEqAbs(@as(f64, 183.22), candles[0].close, 0.01);
-    try std.testing.expectEqual(@as(u64, 217307380), candles[0].volume);
+    try std.testing.expectEqual(@as(usize, 3), triple.candles.len);
+    try std.testing.expectEqual(@as(usize, 0), triple.dividends.len);
+    try std.testing.expectEqual(@as(usize, 1), triple.splits.len);
+
+    const split = triple.splits[0];
+    try std.testing.expect(split.date.eql(Date.fromYmd(2017, 10, 16)));
+    try std.testing.expectApproxEqAbs(@as(f64, 4.0), split.numerator, 0.001);
+    try std.testing.expectApproxEqAbs(@as(f64, 1.0), split.denominator, 0.001);
+    try std.testing.expectApproxEqAbs(@as(f64, 4.0), split.ratio(), 0.001);
 }
 
-test "parseCandles error response" {
+test "parseAll extracts reverse 1:10 split (splitFactor < 1)" {
+    // Reverse split: 1:10 means splitFactor = 0.1
+    const body =
+        \\[
+        \\  {
+        \\    "date": "2024-06-10T00:00:00.000Z",
+        \\    "close": 50.0, "open": 5.0, "high": 50.0, "low": 5.0,
+        \\    "volume": 1000, "adjClose": 50.0,
+        \\    "divCash": 0.0, "splitFactor": 0.1
+        \\  }
+        \\]
+    ;
+
+    const allocator = std.testing.allocator;
+    const triple = try parseAll(allocator, body);
+    defer allocator.free(triple.candles);
+    defer Dividend.freeSlice(allocator, triple.dividends);
+    defer allocator.free(triple.splits);
+
+    try std.testing.expectEqual(@as(usize, 1), triple.splits.len);
+    const split = triple.splits[0];
+    try std.testing.expectApproxEqAbs(@as(f64, 0.1), split.ratio(), 0.001);
+}
+
+test "parseAll: combined dividend + split in same response" {
+    const body =
+        \\[
+        \\  {"date": "2024-01-15T00:00:00.000Z", "close": 100.0, "open": 100.0, "high": 100.0, "low": 100.0,
+        \\   "volume": 0, "adjClose": 100.0, "divCash": 0.5, "splitFactor": 1.0},
+        \\  {"date": "2024-06-10T00:00:00.000Z", "close": 25.0, "open": 100.0, "high": 100.0, "low": 25.0,
+        \\   "volume": 0, "adjClose": 25.0, "divCash": 0.0, "splitFactor": 4.0},
+        \\  {"date": "2024-12-15T00:00:00.000Z", "close": 30.0, "open": 30.0, "high": 30.0, "low": 30.0,
+        \\   "volume": 0, "adjClose": 30.0, "divCash": 0.15, "splitFactor": 1.0}
+        \\]
+    ;
+
+    const allocator = std.testing.allocator;
+    const triple = try parseAll(allocator, body);
+    defer allocator.free(triple.candles);
+    defer Dividend.freeSlice(allocator, triple.dividends);
+    defer allocator.free(triple.splits);
+
+    try std.testing.expectEqual(@as(usize, 3), triple.candles.len);
+    try std.testing.expectEqual(@as(usize, 2), triple.dividends.len);
+    try std.testing.expectEqual(@as(usize, 1), triple.splits.len);
+
+    try std.testing.expectApproxEqAbs(@as(f64, 0.5), triple.dividends[0].amount, 0.001);
+    try std.testing.expectApproxEqAbs(@as(f64, 0.15), triple.dividends[1].amount, 0.001);
+    try std.testing.expectApproxEqAbs(@as(f64, 4.0), triple.splits[0].ratio(), 0.001);
+}
+
+test "parseAll: large dividend (VPMAX-style cap-gains distribution)" {
+    // VPMAX's 2025-12-17 distribution of $30.43 — chunky year-end
+    // cap-gains payout that inflates 1Y total return because Tiingo
+    // (and Polygon) lump it under regular dividends.
+    const body =
+        \\[
+        \\  {"date": "2025-12-17T00:00:00.000Z", "close": 214.0, "open": 244.43, "high": 244.43, "low": 213.5,
+        \\   "volume": 0, "adjClose": 214.0, "divCash": 30.429903, "splitFactor": 1.0}
+        \\]
+    ;
+
+    const allocator = std.testing.allocator;
+    const triple = try parseAll(allocator, body);
+    defer allocator.free(triple.candles);
+    defer Dividend.freeSlice(allocator, triple.dividends);
+    defer allocator.free(triple.splits);
+
+    try std.testing.expectEqual(@as(usize, 1), triple.dividends.len);
+    try std.testing.expectApproxEqAbs(@as(f64, 30.429903), triple.dividends[0].amount, 0.000001);
+}
+
+test "parseAll error response" {
     const body =
         \\{"detail": "Not found."}
     ;
 
     const allocator = std.testing.allocator;
-    const result = parseCandles(allocator, body);
+    const result = parseAll(allocator, body);
     try std.testing.expectError(error.RequestFailed, result);
 }
 
-test "parseCandles empty array" {
+test "parseAll empty array" {
     const body = "[]";
     const allocator = std.testing.allocator;
-    const candles = try parseCandles(allocator, body);
-    defer allocator.free(candles);
-    try std.testing.expectEqual(@as(usize, 0), candles.len);
+    const triple = try parseAll(allocator, body);
+    defer allocator.free(triple.candles);
+    defer Dividend.freeSlice(allocator, triple.dividends);
+    defer allocator.free(triple.splits);
+
+    try std.testing.expectEqual(@as(usize, 0), triple.candles.len);
+    try std.testing.expectEqual(@as(usize, 0), triple.dividends.len);
+    try std.testing.expectEqual(@as(usize, 0), triple.splits.len);
 }
diff --git a/src/service.zig b/src/service.zig
index eda1a56..c37e770 100644
--- a/src/service.zig
+++ b/src/service.zig
@@ -352,10 +352,23 @@ pub const DataService = struct {
     fn fetchFromProvider(self: *DataService, comptime T: type, symbol: []const u8) !cache.Store.DataFor(T) {
         return switch (T) {
             Dividend => {
+                // Polygon is the primary source: it carries
+                // forward-looking declared dividends (e.g. ARCC's
+                // 2026-06-15 ex_date), which Tiingo's price-series
+                // response does not. Tiingo opportunistically
+                // supplements the cache via `populateAllFromTiingo`
+                // when candle fetches happen — that path uses the
+                // sorted-union write semantics in
+                // `cache.Store.writeMerged`, so Polygon's entries
+                // and Tiingo's entries coexist in `dividends.srf`
+                // without overwriting each other.
                 var pg = try self.getProvider(Polygon);
                 return pg.fetchDividends(self.allocator, symbol, null, null);
             },
             Split => {
+                // Same rationale as Dividend above. Polygon also
+                // carries forward-looking split announcements that
+                // Tiingo's price-series doesn't surface.
                 var pg = try self.getProvider(Polygon);
                 return pg.fetchSplits(self.allocator, symbol);
             },
@@ -367,6 +380,57 @@ pub const DataService = struct {
         };
     }
 
+    /// Fetch candles, dividends, and splits from Tiingo in a single
+    /// HTTP call and write all three caches. Returns the triple so
+    /// the caller can use the data without re-reading from disk.
+    ///
+    /// This is the orchestrated "cold cache" path. `getCandles`
+    /// (cold-cache full fetch) calls this so a single Tiingo HTTP
+    /// request populates `candles_daily.srf`, `candles_meta.srf`,
+    /// `dividends.srf`, and `splits.srf` together. Tiingo's
+    /// per-row `divCash` and `splitFactor` make this almost free.
+    ///
+    /// For dividends and splits the writes go through
+    /// `writeWithSource` with `"tiingo"` as the source hint. The
+    /// underlying `writeMerged` primitive merges Tiingo's view
+    /// into whatever's already on disk (typically Polygon-sourced
+    /// records), preserving forward-looking entries Polygon
+    /// uniquely carries. New entries trigger an `info(cache)` log
+    /// line attributing the discovery to Tiingo — useful when
+    /// Tiingo surfaces a corporate action Polygon missed (the
+    /// canonical case is SPYM's 2017-10-16 4:1 split).
+    ///
+    /// `from` is fixed at 2000-01-01 to cover any 10Y trailing-return
+    /// window even when `--as-of` back-dates the reference to the
+    /// earliest imported portfolio data (currently 2014). The extra
+    /// few years of pre-2004 candles cost ~150 KB per symbol on disk
+    /// and a one-time bandwidth bump on cold-cache fetch, both
+    /// trivial. Also gives a comfortable buffer for older corporate
+    /// actions (e.g. SPYM's 2017-10-16 split, deep-history reverse
+    /// splits on legacy tickers).
+    fn populateAllFromTiingo(self: *DataService, symbol: []const u8) !@import("providers/tiingo.zig").CandleAndCorporateActions {
+        var tg = try self.getProvider(Tiingo);
+        const today = fmt.todayDate(self.io);
+        const from = Date.fromYmd(2000, 1, 1);
+        const triple = try tg.fetchCandlesAndCorporateActions(self.allocator, symbol, from, today);
+
+        var s = self.store();
+        // Candles + meta — `cacheCandles` writes both candles_daily.srf
+        // and candles_meta.srf in one shot (last_close, last_date,
+        // provider, fail_count=0).
+        if (triple.candles.len > 0) {
+            s.cacheCandles(symbol, triple.candles, .tiingo, 0);
+        }
+        // Dividends and splits use the merge write path so Tiingo's
+        // view supplements rather than replaces existing (typically
+        // Polygon-sourced) records. New entries are logged with
+        // "tiingo" attribution.
+        s.writeWithSource(Dividend, symbol, triple.dividends, cache.DataType.dividends.ttl(), "tiingo");
+        s.writeWithSource(Split, symbol, triple.splits, cache.DataType.splits.ttl(), "tiingo");
+
+        return triple;
+    }
+
     /// Invalidate cached data for a symbol so the next get* call forces a fresh fetch.
     pub fn invalidate(self: *DataService, symbol: []const u8, data_type: cache.DataType) void {
         var s = self.store();
@@ -574,33 +638,39 @@ pub const DataService = struct {
             log.debug("{s}: candles synced from server but stale, falling through to full fetch", .{symbol});
         }
 
-        // No usable cache — full fetch (~10 years, plus buffer for leap years)
+        // No usable cache — full fetch via the orchestrated Tiingo
+        // helper, which writes candles + dividends + splits caches in
+        // one shot from a single HTTP response. The fixed start date
+        // (see `populateAllFromTiingo`) is 2000-01-01, deep enough to
+        // cover a 10Y trailing-return window even when `--as-of`
+        // back-dates the reference into 2014-era imported portfolio
+        // history, plus a buffer for older corporate actions like
+        // SPYM's 2017-10-16 split.
         log.debug("{s}: fetching full candle history from provider", .{symbol});
-        const from = today.addDays(-3700);
 
-        const result = self.fetchCandlesFromProviders(symbol, from, today, .tiingo) catch |err| {
-            if (err == DataError.TransientError) {
-                // On a fresh fetch, increment fail_count if we have meta
+        const triple = self.populateAllFromTiingo(symbol) catch |err| {
+            if (err == error.RateLimited or err == error.ServerError or err == error.RequestFailed) {
+                // Transient: increment fail_count on existing meta so
+                // we know to back off if this keeps happening.
                 if (meta_result) |mr| {
                     const new_fail_count = mr.meta.fail_count +| 1;
                     s.updateCandleMeta(symbol, mr.meta.last_close, mr.meta.last_date, mr.meta.provider, new_fail_count);
                 }
                 return DataError.TransientError;
             }
-            // FetchFailed at this point means BOTH Tiingo and Yahoo
-            // returned NotFound (or Yahoo was unavailable on top of
-            // Tiingo NotFound) — symbol genuinely has no candle data
-            // anywhere we look. Negative-cache the result so we don't
-            // keep retrying nonexistent symbols.
+            // NotFound, ParseError, InvalidResponse, AuthError —
+            // symbol genuinely has no candle data on Tiingo (the only
+            // provider for historical candles since the 2026-05
+            // audit). Negative-cache so we don't keep retrying.
             s.writeNegative(symbol, .candles_daily);
             return DataError.FetchFailed;
         };
+        // populateAllFromTiingo writes all three caches itself; we
+        // free the slices we don't return.
+        defer Dividend.freeSlice(self.allocator, triple.dividends);
+        defer self.allocator.free(triple.splits);
 
-        if (result.candles.len > 0) {
-            s.cacheCandles(symbol, result.candles, result.provider, 0); // reset fail_count on success
-        }
-
-        return .{ .data = result.candles, .source = .fetched, .timestamp = std.Io.Timestamp.now(self.io, .real).toSeconds(), .allocator = self.allocator };
+        return .{ .data = triple.candles, .source = .fetched, .timestamp = std.Io.Timestamp.now(self.io, .real).toSeconds(), .allocator = self.allocator };
     }
 
     /// Fetch dividend history for a symbol.