diff --git a/src/components/insights/coach-panel/__tests__/chat-bubble-initials.test.tsx b/src/components/insights/coach-panel/__tests__/chat-bubble-initials.test.tsx
new file mode 100644
index 000000000..badd7f82c
--- /dev/null
+++ b/src/components/insights/coach-panel/__tests__/chat-bubble-initials.test.tsx
@@ -0,0 +1,52 @@
+import { describe, it, expect, vi } from "vitest";
+import { renderToStaticMarkup } from "react-dom/server";
+
+import { I18nProvider } from "@/lib/i18n/context";
+
+/**
+ * The person's bubble falls back to initials of the name the app shows, like
+ * the top bar, never the login: a managed record's login is a generated
+ * handle, and "MA" for `managed-…` is nobody's initials.
+ */
+const auth = vi.hoisted(() => ({
+  user: {
+    id: "u1",
+    username: "managed-1f2e3d",
+    displayName: "Alex Example" as string | null,
+    role: "USER",
+    avatarUrl: null,
+  },
+}));
+
+vi.mock("@/hooks/use-auth", () => ({
+  useAuth: () => ({ user: auth.user, isAuthenticated: true, isLoading: false }),
+}));
+vi.mock("@tanstack/react-query", () => ({
+  useQuery: () => ({ data: undefined }),
+  useMutation: () => ({ mutate: vi.fn(), isPending: false, isError: false }),
+  useQueryClient: () => ({ invalidateQueries: vi.fn() }),
+}));
+
+import { ChatBubble } from "../chat-bubble";
+
+function userBubble(): string {
+  return renderToStaticMarkup(
+    <I18nProvider initialLocale="en">
+      <ChatBubble role="user" content="How did I sleep?" />
+    </I18nProvider>,
+  );
+}
+
+describe("coach bubble initials", () => {
+  it("spells the display name, not the login", () => {
+    const html = userBubble();
+    expect(html).toContain(">AE<");
+    expect(html).not.toContain(">MA<");
+  });
+
+  it("falls back to the login when there is no display name", () => {
+    auth.user.displayName = null;
+    auth.user.username = "sam";
+    expect(userBubble()).toContain(">S<");
+  });
+});
diff --git a/src/components/insights/coach-panel/__tests__/message-thread.test.tsx b/src/components/insights/coach-panel/__tests__/message-thread.test.tsx
index f26660ff9..9c28c40b1 100644
--- a/src/components/insights/coach-panel/__tests__/message-thread.test.tsx
+++ b/src/components/insights/coach-panel/__tests__/message-thread.test.tsx
@@ -551,10 +551,11 @@ describe("<MessageThread>", () => {
   });
 
   it("falls back to initials when no avatar URL is present", () => {
-    // Default mock returns avatarUrl: null → initials path.
+    // Default mock returns avatarUrl: null → initials path, spelled like the
+    // top bar's: one word, one letter.
     const html = render(<MessageThread conversation={baseConversation} />);
     expect(html).toContain('data-slot="coach-bubble-user-avatar"');
-    expect(html).toMatch(/data-slot="coach-bubble-user-avatar"[^>]*>TE</);
+    expect(html).toMatch(/data-slot="coach-bubble-user-avatar"[^>]*>T</);
   });
 
   // v1.4.25 — optimistic user bubble appears before the "Thinking…"
diff --git a/src/components/insights/coach-panel/chat-bubble.tsx b/src/components/insights/coach-panel/chat-bubble.tsx
index 21f341c8f..a150b6abc 100644
--- a/src/components/insights/coach-panel/chat-bubble.tsx
+++ b/src/components/insights/coach-panel/chat-bubble.tsx
@@ -9,6 +9,7 @@ import { cn } from "@/lib/utils";
 import { Button } from "@/components/ui/button";
 import { useTranslations } from "@/lib/i18n/context";
 import { useAuth } from "@/hooks/use-auth";
+import { accountName, nameInitials } from "@/lib/account-name";
 import {
   parseChartTokens,
   tokenToMetric,
@@ -388,12 +389,10 @@ function ChatBubbleImpl({
   if (role === "user") {
     // v1.5.5 — pull the user's self-hosted avatar so the user
     // bubble matches the Coach avatar in size and visual weight.
-    // Falls back to initials when the user has not uploaded an
-    // avatar. Replaces the Gravatar leak (v1.4.22 B3).
+    // Falls back to the display name's initials, as the top bar does, when
+    // the user has not uploaded an avatar.
     const avatarUrl = user?.avatarUrl ?? null;
-    const initials = user?.username
-      ? user.username.slice(0, 2).toUpperCase()
-      : null;
+    const initials = user ? nameInitials(accountName(user)) || null : null;
     return (
       <div
         data-slot="coach-bubble-user"