An incorporated e-commerce owner can have a healthy bank balance and still have much less cash available than the balance suggests. The account may include GST/HST collected, amounts needed for corporate tax, inventory commitments, and money that will create personal tax when paid to the owner.
The useful question is therefore not “How much cash is in the bank?” It is “How much remains after obligations and near-term operating needs?”
Start with four separate cash buckets
Indirect tax. Track GST/HST collected and recoverable input tax credits separately. A platform payout or bank deposit does not show the net amount that will be payable on the return.
Corporate income tax. Estimate taxable income from current books, then adjust for items whose accounting and tax treatment differ. The estimate should be refreshed as margins, advertising, foreign exchange, inventory, and owner compensation change.
Corporate tax instalments. Many corporations must pay tax during the year rather than waiting for the return. The CRA explains the available instalment calculation methods and applicable thresholds in its corporation instalment guidance.
Owner-level tax. Salary, dividends, shareholder advances, and expense reimbursements do not have the same tax result. Money moving from the corporation to the owner needs a clear classification and an estimate of the related personal tax.
Use current results, not last year’s percentage
A flat percentage of sales is usually too crude. Revenue can rise while taxable profit falls because of advertising, returns, freight, or inventory write-downs. It can also understate tax when margins improve.
A better reserve starts with a reliable monthly close:
- Reconcile Amazon, Shopify, and payment processor activity to the bank.
- Record revenue, refunds, fees, advertising, and foreign exchange in the correct period.
- Update inventory and cost of goods sold.
- Estimate year-to-date taxable income and the remaining year.
- Compare expected tax with payments and instalments already made.
- Keep the tax reserve outside the amount treated as available for owner withdrawals or inventory purchases.
The reserve is an estimate, not a single annual number. It should change when the forecast changes.
Add the operating cash the store still needs
Tax is only one claim on cash. Before deciding what can be withdrawn, include supplier deposits, freight and duty, advertising, payroll, debt payments, refunds, and the next inventory order. An incorporated seller can be profitable on paper and still need most of the bank balance to fund the next buying cycle.
A useful monthly owner view shows:
- cash in bank;
- GST/HST and other tax balances;
- estimated corporate tax and upcoming instalments;
- committed inventory and operating payments;
- a working capital buffer; and
- the residual amount that may be available to retain or pay to the owner.
Review the estimate before decisions become irreversible
Review the reserve before a large withdrawal, inventory order, bonus, dividend, or year-end. The earlier review creates room to change the timing or amount. Waiting until the corporate return is prepared turns planning into a calculation of what already happened.
The exact reserve depends on the corporation’s province, taxable income, prior-year balances, instalment position, owner compensation, and filing history. Those facts should be connected to current books before deciding that cash is available.