diff --git a/src/main.zig b/src/main.zig
index 0980dd9..18f8ec9 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -67,7 +67,9 @@ fn handleHelp(_: *App, _: *httpz.Request, res: *httpz.Response) !void {
         \\Returns fields:
         \\  trailing{1,3,5,10}YearReturn    Total return with dividend reinvestment
         \\  price{1,3,5,10}YearReturn       Price-only return (from adjusted close)
-        \\  volatility                       3-year annualized volatility
+        \\  volatility                      Longest-term available annualized volatility
+        \\  volatilityTerm                  Period (years) of the volatility field
+        \\  volatility{1,3,5,10}Year        Per-period annualized volatility
         \\
         \\XML example (LibreCalc):
         \\  =FILTERXML(WEBSERVICE("http://host/AAPL/returns?fmt=xml"),"//total10YearReturn")
@@ -158,7 +160,16 @@ fn handleReturns(app: *App, req: *httpz.Request, res: *httpz.Response) !void {
     const p3y = if (price_ret.three_year) |r| r.annualized_return else null;
     const p5y = if (price_ret.five_year) |r| r.annualized_return else null;
     const p10y = if (price_ret.ten_year) |r| r.annualized_return else null;
-    const vol = if (risk.three_year) |r| r.volatility else null;
+
+    // Per-period volatility
+    const v1y = if (risk.one_year) |r| r.volatility else null;
+    const v3y = if (risk.three_year) |r| r.volatility else null;
+    const v5y = if (risk.five_year) |r| r.volatility else null;
+    const v10y = if (risk.ten_year) |r| r.volatility else null;
+
+    // Longest-term volatility convenience fields
+    const vol_best = v10y orelse v5y orelse v3y orelse v1y;
+    const vol_term: ?u8 = if (v10y != null) 10 else if (v5y != null) 5 else if (v3y != null) 3 else if (v1y != null) 1 else null;
 
     // Total returns with dividend reinvestment (non-fatal if dividends unavailable).
     // trailing* fields use total return when available, falling back to price-only.
@@ -201,6 +212,11 @@ fn handleReturns(app: *App, req: *httpz.Request, res: *httpz.Response) !void {
                 \\  <price5YearReturn>{s}</price5YearReturn>
                 \\  <price10YearReturn>{s}</price10YearReturn>
                 \\  <volatility>{s}</volatility>
+                \\  <volatilityTerm>{s}</volatilityTerm>
+                \\  <volatility1Year>{s}</volatility1Year>
+                \\  <volatility3Year>{s}</volatility3Year>
+                \\  <volatility5Year>{s}</volatility5Year>
+                \\  <volatility10Year>{s}</volatility10Year>
                 \\</returns>
                 \\
             , .{
@@ -214,7 +230,12 @@ fn handleReturns(app: *App, req: *httpz.Request, res: *httpz.Response) !void {
                 fmtPct(arena, p3y),
                 fmtPct(arena, p5y),
                 fmtPct(arena, p10y),
-                fmtPct(arena, vol),
+                fmtPct(arena, vol_best),
+                fmtInt(arena, vol_term),
+                fmtPct(arena, v1y),
+                fmtPct(arena, v3y),
+                fmtPct(arena, v5y),
+                fmtPct(arena, v10y),
             });
             return;
         }
@@ -222,7 +243,7 @@ fn handleReturns(app: *App, req: *httpz.Request, res: *httpz.Response) !void {
 
     res.content_type = httpz.ContentType.JSON;
     res.body = try std.fmt.allocPrint(arena,
-        \\{{"ticker":"{s}","returnDate":"{s}","trailing1YearReturn":{s},"trailing3YearReturn":{s},"trailing5YearReturn":{s},"trailing10YearReturn":{s},"price1YearReturn":{s},"price3YearReturn":{s},"price5YearReturn":{s},"price10YearReturn":{s},"volatility":{s}}}
+        \\{{"ticker":"{s}","returnDate":"{s}","trailing1YearReturn":{s},"trailing3YearReturn":{s},"trailing5YearReturn":{s},"trailing10YearReturn":{s},"price1YearReturn":{s},"price3YearReturn":{s},"price5YearReturn":{s},"price10YearReturn":{s},"volatility":{s},"volatilityTerm":{s},"volatility1Year":{s},"volatility3Year":{s},"volatility5Year":{s},"volatility10Year":{s}}}
     , .{
         symbol,
         date_str,
@@ -234,7 +255,12 @@ fn handleReturns(app: *App, req: *httpz.Request, res: *httpz.Response) !void {
         fmtPct(arena, p3y),
         fmtPct(arena, p5y),
         fmtPct(arena, p10y),
-        fmtPct(arena, vol),
+        fmtPct(arena, vol_best),
+        fmtInt(arena, vol_term),
+        fmtPct(arena, v1y),
+        fmtPct(arena, v3y),
+        fmtPct(arena, v5y),
+        fmtPct(arena, v10y),
     });
 }
 
@@ -323,6 +349,12 @@ fn fmtPct(arena: std.mem.Allocator, value: ?f64) []const u8 {
     return "null";
 }
 
+/// Format an optional integer, or "null" if absent.
+fn fmtInt(arena: std.mem.Allocator, value: ?u8) []const u8 {
+    if (value) |v| return std.fmt.allocPrint(arena, "{d}", .{v}) catch "null";
+    return "null";
+}
+
 /// Append a watch lot for the given symbol to the portfolio SRF file,
 /// unless it already exists. Best-effort — errors are logged, not fatal.
 fn appendWatchSymbol(symbol: []const u8) !void {