An SBA underwriter’s job is to poke holes. They inherit a Form 1919 that projects a 1.25x DSCR—solid on the surface—but one line item is missing its justification, and suddenly the entire projection is suspect. The underwriter doesn’t trust assumptions they have to guess at. They request supplemental documentation, timeline slips, and in the worst cases, the file gets sent back to the broker with a list of “clarifications” that weren’t hard questions but missed steps upfront. The real cost isn’t the back-and-forth: it’s the deal’s credibility. Once an underwriter decides an assumption is shaky, they’re reading the rest of the projection through that lens. Documenting projection assumptions isn’t a compliance checkbox. It’s the defense of your cash flow story before anyone attacks it.
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The Three-Layer Documentation Structure
Start by organizing assumptions into three tiers: macro (external economic facts), operator (company-specific, borrower-controlled), and transactional (deal-specific inputs). Underwriters expect each layer documented differently, and conflating them wastes credibility.
Macro assumptions are market rates, industry benchmarks, or external data you’re not inventing. An example: you’re projecting that a construction services business’s material costs will rise 3% annually. Source this. Link it to a Bureau of Labor Statistics producer price index for the relevant commodity, cite a trade association survey, or reference an industry trend report you found. The underwriter doesn’t have to trust your opinion—they trust the source. If you’re using a percentage from a real market report, include the publication date, the report name, and the specific page or metric. A sentence like “Per the AGC Construction Cost Index from Q3 2025, materials costs are expected to rise 2.8% annually through 2027” is defensible. “Materials typically go up 3% per year” is not.
Operator assumptions are about how the borrower’s business behaves: labor efficiency, customer retention, pricing power, or operational leverage. These must tie to the borrower’s history and the quality of the manager. If you’re projecting that a consulting firm will grow revenue 12% year-over-year, reference historical growth (past 2–3 years of tax returns), any contracts in hand (attach a letter of intent or signed engagement), and the borrower’s depth in that vertical. If the business is new or has no track record, you’ll need either a comparable operator story (someone with that background in a similar business) or a written narrative from the borrower explaining their market entry plan, client acquisition pipeline, and proof of concept—even if it’s small-scale or pre-revenue data.
Transactional assumptions are specific to this deal: loan proceeds, term, any SBA guaranty structure elements, or post-close business changes (relocation, staff hire, new equipment deployment). Document how the loan proceeds are allocated (equipment, inventory, working capital, payoff), reference the purchase agreement or equipment quotes, and explain how proceeds directly tie to the cash flow drivers in the projection. If the borrower is hiring a new manager post-close and you’re projecting improved efficiency, attach a job offer or employment agreement. If you’re assuming a customer contract, attach the contract or a signed letter of intent.
The Assumption Checklist: What an Underwriter Reads First
Most brokers send projections with no cover document. A one-page summary—placed at the very front of the projection package—cuts review time and preempts objections. This isn’t a narrative; it’s a structured list.
- Revenue assumptions: List each revenue stream separately. For each, state the unit count or volume (customers, units sold, billable hours), the assumed price per unit, and the source or justification. Example: “Lawn care revenue assumes 120 active customer accounts at $85/month recurring, based on 3-year average account base (see P&Ls attached) plus 20 new accounts annually at conservative $65/month pricing reflecting Q4 sales pipeline (see prospect list attached).”
- COGS and operating expense assumptions: Show the gross margin by year. If margins are compressing or expanding, explain why. State labor costs as headcount and wage (or percentage of revenue if that’s your model) and justify any wage growth. Tie rent or occupancy costs to a lease or market comparable. For everything else—insurance, utilities, software, professional services—state it as a percentage of revenue or fixed dollars and note whether you’ve observed this ratio in the tax returns or market data.
- Working capital and seasonal timing: If cash flow is lumpy (consulting retainers received quarterly, payroll weekly), note the cash conversion cycle and how it affects debt service coverage in lower-revenue months. This prevents underwriters from assuming linear monthly cash flow and then surprising the borrower with DSCR calculated on the worst-case month.
- Capital expenditures and debt service: Show replacement capex assumptions (as a percentage of revenue or fixed dollars per year). Note any extraordinary capex planned during the projection period and tie it to a business need or maintenance schedule. Show the requested loan’s term, rate, and amortization schedule, and confirm DSCR is calculated using the full P&L with the debt service baked in.
- Known changes or one-off events: If a major customer is leaving, a lease renewal is coming at higher rent, or a new product launch is planned, call it out explicitly. Underwriters hate discovering surprises in line items; they hate them more when they feel like you hid them.
A Worked Example: Restaurant Projection
Imagine a franchisee buying into an established quick-service restaurant brand and assuming they’ll hit $850k in year-one revenue. Here’s how to document that assumption without leaving the underwriter guessing.
Raw assumption: “Year 1 revenue: $850,000.”
Documented version:
“Based on (1) the franchisor’s AUV (average unit volume) of $920k for similar locations (per franchise disclosure document, Exhibit A), (2) this location’s 90-day ramp-up period (reduced volume Q1), and (3) a 7% below-average performance assumption reflecting new-owner risk in a new market (see comparable new franchisee locations’ P&Ls, years 1–2, in Exhibit B), we project $850k year 1. This represents a 92% AUV in year 1, recovering to 98% AUV by year 2 ($900k) as the owner and staff gain experience and local customer base deepens. Food cost is projected at 28% of revenue (vs. brand standard 26%) to reflect higher waste and learning curve in year 1 and 27% in years 2–3 (converging to brand standard). Labor is 32% of revenue year 1 (vs. 30% target) and steps down 0.5% annually as cross-training and systems maturity reduce overtime.”
That’s documentable. It cites the franchisor’s own benchmark, applies a discount for risk, references comparable operators, and explains margin differences with specific reasoning. An underwriter reading this doesn’t need to ask follow-up questions on the revenue line; they know where the 850k comes from and whether they believe the risk discount is appropriate.
Common Documentation Gaps That Trigger Underwriter Scrutiny
Margin improvements without explanation: If gross margin jumps from 35% to 42%, you must explain why. Is it a pricing increase, improved product mix, automation, or reduced waste? Without this, the underwriter assumes it’s made up. Tie it to a specific operational change, a contract signed at higher rates, or a documented efficiency project the borrower is implementing.
Revenue growth that outpaces comparable operators: If you’re projecting 25% annual growth in a mature industry, show evidence the borrower or a direct peer has achieved it. Pull comparable company financials from SEC filings, industry reports, or SBA loan data if it’s publicly available. Don’t just assert market opportunity; show traction.
Seasonal adjustment without a cash flow waterfall: Many businesses are seasonal. If you’re using an annual average for DSCR but the business carries a debt service payment in its worst cash month, document the monthly cash flow—not just annual. An underwriter may be fine with an average DSCR of 1.25x if the worst quarter still covers debt, but if you hide the seasonal dip, they’ll recalculate and reject the file.
Expense ratios that differ from tax returns without callout: If the current P&L shows 40% occupancy expense but the projection shows 32%, explain the change. Is the company relocating to cheaper space? Are they spreading overhead over higher revenue? Again, don’t make the underwriter reverse-engineer your assumptions.
Organizing Your Documentation Package
Bundle assumptions with source documents in a consistent order. A typical package looks like: (1) Assumption summary page (the checklist above), (2) Pro forma P&L and cash flow, (3) Historical P&Ls and tax returns (last 2–3 years), (4) External data or benchmarks (BLS reports, franchise disclosures, industry surveys, comparable company financials), (5) Borrower-provided documentation (contracts, letters of intent, employment agreements, purchase agreements, equipment quotes). If the file is thick, add a table of contents and cross-reference it in the assumption summary. An underwriter who can find the source for an assumption in 30 seconds trusts the assumption more than one who has to dig.
The goal is simple: make it impossible for the underwriter to say “I don’t know where that number came from.” When every assumption is sourced and every source is attached, the underwriter is evaluating your judgment and the borrower’s capability, not questioning the math.
This article is educational and does not constitute lending advice — confirm current SBA program requirements with your lender before submitting a file.
Frequently Asked Questions
What’s the difference between assumptions that underwriters will question and ones they’ll accept at face value?
Underwriters accept assumptions tied to verifiable external data (government statistics, industry benchmarks, public filings) or the borrower’s own track record (historical tax returns, signed contracts). They question assumptions that are unique to the borrower, have no precedent in their financials, or rely on opinions rather than evidence. If you’re projecting a behavior the borrower has demonstrated before, cite the history. If it’s new, provide a comparable example or a written business plan from the borrower.
How much historical data do I need to justify an assumption?
Two to three years of tax returns establish a pattern. One year is a starting point; four or more years strengthens your case for borrowers with long operating history. For new businesses or major strategy changes, look for comparable operator examples (other businesses in the space with published financials or SBA loans) or pilot data the borrower has generated. One month of actual results at a new location beats guessing; six months is even better.
Should I include industry benchmarks in every projection, or only when my assumptions differ from them?
Include benchmarks whenever your assumptions are material to debt service coverage or credit decision. At a minimum, cite them for gross margin, labor as a percentage of revenue, and occupancy costs—the big three that underwriters compare across industries. If your margins are in line with industry averages, note it (it’s credibility). If they differ significantly, a benchmark forces you to explain the gap rather than assuming the underwriter won’t notice.
Can I use pro forma financials from the seller or franchisor as support for my revenue assumptions?
Yes, but separately. Attach them and note their source clearly (e.g., “Franchisor’s provided AUV estimate, Franchise Disclosure Document”). Underwriters know seller-provided projections are optimistic, so disclose them, adjust for conservatism, and explain your adjustment. Don’t hide the optimistic number or present it as your own analysis. Transparency here actually strengthens credibility.
What if a projection assumption is based on a borrower’s stated plan but has no documented evidence yet?
Get a letter from the borrower on their letterhead. Have them describe the plan, the timeline, and why it’s achievable. If it’s a hiring plan, attach a job description or offer letter. If it’s a customer acquisition or product launch, get them to outline their strategy and any pre-launch evidence (prototype feedback, letters of interest, advisory board notes). This turns a verbal assumption into a documented one and forces the borrower to commit in writing—which also benefits you if the deal ever comes under legal scrutiny.
This article is educational and does not constitute lending advice — confirm current SBA program requirements with your lender before submitting a file.
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