Business, Main Street / SMB

How to Underwrite a Small Business Acquisition (SBA)

Underwrite a small business by rebuilding seller's discretionary earnings from tax returns, removing unsupported add-backs, then subtracting a market salary for the new owner and debt service. The metrics that matter most are verified SDE, DSCR after owner compensation, and how dependent revenue is on the departing owner and a few customers.

What makes small business underwriting different

Businesses under about $5 million of revenue are usually sold on seller's discretionary earnings, the profit available to one full-time owner before debt. That makes the add-back schedule the center of the underwriting. Owners run personal expenses, family payroll and one-time costs through the business, and some of those add-backs are real while others are optimistic. Financial statements are often tax-driven and unaudited, so tax returns become the anchor. The other dominant risk is the owner: in many small companies the seller holds the customer relationships, the licenses, the pricing knowledge and the vendor terms, and value can leave with them.

Lenders, particularly SBA 7(a) lenders, focus on whether verified cash flow covers the new debt with a cushion after paying the buyer a reasonable salary, and on the buyer's industry experience and equity injection. They tie the analysis to tax returns and often discount add-backs they cannot document. Equity buyers, including searchers and small holdcos, look at the purchase multiple, the transition plan and growth levers like price increases or adding a sales function. Equity tolerates more owner dependence if a seller note and transition period align the seller, while a lender wants the business to service debt even if the seller leaves early.

Key metrics

Seller's discretionary earnings (SDE)

SDE is the earnings base buyers pay a multiple on, so every add-back must be traced to a tax return line or invoice.

DSCR after owner salary

Coverage only means something after the new owner is paid a market wage to do the seller's job.

SBA lenders commonly look for 1.25x or better, and many prefer 1.5x or more on acquisitions.

Purchase multiple of SDE

The multiple shows how many years of owner earnings the buyer is paying for and how much risk is left in the deal.

Main street businesses often trade at roughly 2x to 4x SDE depending on size, sector and transferability.

Customer concentration

Small businesses can depend on one or two accounts that may leave with an ownership change.

Underwriters often flag any single customer above about 10 to 15 percent of revenue.

Tax return to P&L reconciliation

Gaps between internal statements and filed returns reveal unreported cash or inflated books.

Equity injection

Buyer cash in the deal shows commitment and gives the lender a cushion against overpaying.

SBA acquisitions typically require at least 10 percent equity injection, with seller notes counting only under specific conditions.

How to underwrite it, step by step

Collect three years of business tax returns and reconcile them to the internal P&L and bank deposits.
Build the SDE bridge line by line and keep only add-backs supported by documentation.
Deduct a market salary for the owner role and any staff needed to replace the seller's work.
Analyze customer, supplier and employee concentration and test what happens if the top account leaves.
Review the lease, licenses and contracts for assignment and change of control terms.
Set a normal working capital level and confirm it transfers with the business.
Model DSCR at the proposed price and structure, including any seller note on standby.
Assess the buyer's experience and the seller's transition commitment before finalizing terms.

Due diligence checklist

Three years of business tax returns
Year-to-date P&L and balance sheet
Bank statements for at least 12 months
SDE add-back schedule with supporting invoices
Customer sales by account for three years
Payroll register and organization chart
Real estate lease and landlord consent terms
Business licenses and permits
Accounts receivable and payable aging
Equipment and inventory list
Buyer resume and personal financial statement
Draft purchase agreement and seller transition agreement

Key risks and mitigants

Seller holds key relationships and the business declines after closing.

Require a transition period, an employment or consulting agreement, and part of the price in a seller note or earnout.

Add-backs are overstated and real earnings are lower.

Accept only documented add-backs and size debt on the conservative SDE figure.

Lease cannot be assigned or will reprice sharply.

Make landlord consent and a new lease with adequate term a closing condition.

Customer concentration in one or two accounts.

Call key customers in diligence, haircut their revenue in the base case, and tie part of the price to retention.

Buyer lacks industry experience to run the business.

Require a credible operating plan, retained managers, or an experienced partner.

Typical financing and deal structure

Most small business acquisitions are financed with SBA 7(a) loans, which allow up to 10 year terms for business assets and longer when real estate is included, with a buyer equity injection and often a seller note. Lenders may require the seller note to be on full standby for a period to count toward equity. Conventional bank loans appear where the buyer has strong collateral or the deal is small. Earnouts are used when revenue depends on the seller's relationships. Personal guarantees from owners of 20 percent or more are standard on SBA loans. Typical covenants include annual financial reporting, minimum DSCR on conventional loans, and life insurance on the key owner.

Red flags

Tax returns show materially less profit than the broker's SDE and the seller attributes the gap to unreported cash.
One customer accounts for a large share of revenue with no contract.
The seller will not stay for a transition period.
Lease expires within a short time with no renewal and the landlord has not agreed to assignment.
Revenue declining in the latest year while the asking price is based on the peak year.

Frequently asked questions

What is SDE and how is it different from EBITDA?

Seller's discretionary earnings is pre-tax profit plus one owner's compensation, interest, depreciation, amortization and documented personal or one-time expenses. EBITDA assumes a paid management team is already in place, so it deducts market salaries for all managers. SDE is used for owner-operated businesses, while EBITDA is used once a business has management that does not depend on the owner.

What DSCR does an SBA 7(a) acquisition loan need?

SBA lenders commonly want debt service coverage of at least 1.25x on historical cash flow after paying the new owner a reasonable salary, and many lenders prefer 1.5x or more for change of ownership loans. Coverage is typically tested on tax return figures, with add-backs only where documented.

How much down payment is needed to buy a small business with an SBA loan?

SBA rules typically require at least a 10 percent equity injection for a change of ownership. A seller note may count toward part of that only if it is on full standby for a period set by the rules. Lenders may ask for more equity if cash flow is thin or the buyer lacks direct experience.

Which add-backs do lenders accept?

Lenders generally accept the owner's salary and benefits, interest, depreciation, amortization, and clearly personal or truly one-time expenses supported by invoices. They push back on vague items like owner travel without receipts, recurring costs labeled as one-time, or wages for family members who actually work in the business and would need to be replaced.

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Educational content, not investment, credit, legal or tax advice. Benchmarks are common practitioner rules of thumb and vary by lender, market and cycle.