5 Common Financial Mistakes of Household Businesses and How to Avoid Them

Vietnam has over 5 million household businesses, but most manage their finances from memory. Below are the 5 most common mistakes I see when advising small merchants — and how to fix them without breaking the bank.

1. Mixing personal and business money

This is the root mistake. Sales revenue, market money, and children's tuition all sitting in the same pocket means you'll never know if your shop is truly profitable or losing money.

The fix: open a separate bank account for your business. Each month, "pay yourself" a fixed amount transferred to your personal account — all household expenses come from there.

2. Not knowing your true cost of goods

Many household business owners calculate cost of goods to include only wholesale purchases, forgetting utilities, rent, spoilage, shipping fees, e-commerce platform fees... so they think they're making 30% profit when it's actually 8%.

The fix: list out all monthly expenses, divide by revenue to get your true expense ratio. Doing this once per quarter is enough to spot trends.

3. Holding too much inventory

Capital sitting in your warehouse is dead capital. Buying in bulk for better pricing but selling slowly means your "savings" turn into interest costs and the risk of outdated merchandise.

The fix: track your average days of inventory on hand. Only consider buying larger quantities for items that turn over in under 45 days.

4. Using informal loans instead of formal credit

When short on working capital, many households choose daily-interest informal loans because they're "quick and easy," when they could actually access household business loans from banks at much lower interest rates.

The fix: maintain sales records (even if just an Excel file or free app) and cash flow through your bank account — this becomes your credit history for bank loans. Prepare in advance of need, don't wait until you're in a cash crunch to ask.

5. Ignoring tax obligations until facing back-assessment

Tax policy for household businesses is changing toward phasing out flat-rate taxes, moving to actual revenue reporting through e-invoicing. Waiting to "see what happens" can lead to back-assessments and penalties.

The fix: proactively learn about the revenue threshold for taxation and filing methods applicable to your business sector; keep input invoices. When revenue grows quickly, consider converting to a formal enterprise to deduct expenses — consult with a tax professional before deciding.

Want to check your shop's financial health? Ask [Sirifin's AI advisor](/vi/ai-advisor) — free, with answers specific to your situation — or [book an appointment with a tax and household business finance expert](/vi/advisors).

Content is for informational and financial education purposes, not tax or legal advice for specific cases.