diff --git a/app/__init__.py b/app/__init__.py
index 1766761..31534e7 100644
--- a/app/__init__.py
+++ b/app/__init__.py
@@ -62,4 +62,15 @@ def create_app(config_name=None):
     def percent_filter(value):
         return format_percent(value)
 
+    @app.template_filter('shares')
+    def shares_filter(value):
+        """Format share quantity — strips trailing zeros, keeps up to 8 decimal places."""
+        try:
+            f = float(value)
+        except (TypeError, ValueError):
+            return '0'
+        # Format to 8 decimal places then strip trailing zeros
+        s = '{:.8f}'.format(f).rstrip('0').rstrip('.')
+        return s if s else '0'
+
     return app
diff --git a/app/templates/investments/detail.html b/app/templates/investments/detail.html
index 4817a95..b1a2b81 100644
--- a/app/templates/investments/detail.html
+++ b/app/templates/investments/detail.html
@@ -31,7 +31,7 @@
             <div class="row g-2 mt-1">
                 <div class="col-6">
                     <div style="font-size:11px;color:var(--muted);text-transform:uppercase;letter-spacing:.06em;">Shares</div>
-                    <div class="mono" style="font-size:16px;font-weight:600;">{{ "%.6f"|format(inv.shares|float)|replace('000000','').rstrip('0').rstrip('.') }}</div>
+                    <div class="mono" style="font-size:16px;font-weight:600;">{{ inv.shares | shares }}</div>
                 </div>
                 <div class="col-6">
                     <div style="font-size:11px;color:var(--muted);text-transform:uppercase;letter-spacing:.06em;">Avg Cost</div>
diff --git a/app/templates/investments/index.html b/app/templates/investments/index.html
index 3791948..19713d3 100644
--- a/app/templates/investments/index.html
+++ b/app/templates/investments/index.html
@@ -135,7 +135,7 @@
                         </div>
                     </td>
                     <td class="text-end mono" style="font-size:12px;color:var(--muted);">
-                        {{ "%.4f"|format(inv.shares|float) | replace('.0000','') }}
+                        {{ inv.shares | shares }}
                     </td>
                     <td class="text-end">
                         {% if inv.current_price %}