diff --git a/app/routes/investments.py b/app/routes/investments.py
index 34a24fd..e41c609 100644
--- a/app/routes/investments.py
+++ b/app/routes/investments.py
@@ -37,6 +37,10 @@ class InvestmentForm(FlaskForm):
     ticker = StringField('Ticker Symbol', validators=[Optional(), Length(max=20)],
                          description='e.g. AAPL, BTC-USD, VNM')
     asset_type = SelectField('Asset Type', choices=ASSET_TYPES, validators=[DataRequired()])
+    shares = DecimalField('Shares / Units', validators=[Optional(), NumberRange(min=0)],
+                          places=8, default=Decimal('0'))
+    avg_cost_basis = DecimalField('Avg Cost per Share', validators=[Optional(), NumberRange(min=0)],
+                                  places=4, default=Decimal('0'))
     notes = TextAreaField('Notes', validators=[Optional()])
     submit = SubmitField('Save')
 
@@ -157,9 +161,18 @@ def edit(id):
         inv.ticker = form.ticker.data.strip().upper() if form.ticker.data else None
         inv.asset_type = form.asset_type.data
         inv.notes = form.notes.data
+        # Manual override of shares/cost basis — only update if user provided values
+        if form.shares.data is not None:
+            inv.shares = form.shares.data
+        if form.avg_cost_basis.data is not None:
+            inv.avg_cost_basis = form.avg_cost_basis.data
         db.session.commit()
         flash('Investment updated.', 'success')
         return redirect(url_for('investments.detail', id=inv.id))
+    # Pre-populate shares/cost for edit form
+    if request.method == 'GET':
+        form.shares.data = inv.shares
+        form.avg_cost_basis.data = inv.avg_cost_basis
     return render_template('investments/form.html', form=form, title='Edit Investment', inv=inv)
 
 
diff --git a/app/templates/investments/form.html b/app/templates/investments/form.html
index a026b8a..04d4d72 100644
--- a/app/templates/investments/form.html
+++ b/app/templates/investments/form.html
@@ -32,6 +32,34 @@
             </div>
         </div>
 
+
+        {% if inv %}
+        <div class="mb-3 p-3" style="background:#f0fdf4;border-radius:8px;border:1px solid #bbf7d0;">
+            <div style="font-size:12px;font-weight:600;color:#166534;margin-bottom:10px;">
+                <i class="bi bi-pencil-square me-1"></i>Manual Override — Shares & Cost Basis
+            </div>
+            <div class="row g-3">
+                <div class="col-6">
+                    {{ form.shares.label(class="form-label fw-medium", style="font-size:13px;") }}
+                    {{ form.shares(class="form-control", placeholder="e.g. 10.5", id="sharesOverride") }}
+                    <small class="text-muted" style="font-size:11px;">Current: {{ inv.shares | shares }}</small>
+                </div>
+                <div class="col-6">
+                    {{ form.avg_cost_basis.label(class="form-label fw-medium", style="font-size:13px;") }}
+                    <div class="input-group">
+                        <span class="input-group-text" style="font-size:12px;">{{ current_user.currency_symbol }}</span>
+                        {{ form.avg_cost_basis(class="form-control", placeholder="e.g. 150.25") }}
+                    </div>
+                    <small class="text-muted" style="font-size:11px;">Current: {{ inv.avg_cost_basis | currency }}</small>
+                </div>
+            </div>
+            <div style="font-size:11px;color:#166534;margin-top:8px;">
+                <i class="bi bi-info-circle me-1"></i>
+                Leave at current values to keep unchanged. These override the transaction log calculation.
+            </div>
+        </div>
+        {% endif %}
+
         <div class="mb-4">
             {{ form.notes.label(class="form-label fw-medium", style="font-size:13px;") }}
             {{ form.notes(class="form-control", rows=2, placeholder="Optional notes") }}