Direct answer: Series A investors audit five areas in financial due diligence: books quality (24 months accrual-basis financials), revenue quality (ARR/MRR reconciled to deferred revenue), unit economics (CAC/LTV/NRR independently calculated), financial model integrity (bottoms-up, formula-driven), and legal completeness (cap table, IP assignments, 409A). The most common diligence killers: ARR that doesn't reconcile to the balance sheet, understated CAC, and missing IP assignments. Startups with a complete data room cut diligence time by 50–70%. Sources: Andreessen Horowitz (November 2025); Burkland Associates (February 2026).
What Do Investors Actually Audit in Series A Diligence?
Highest Risk Area 1: Books Quality
Accrual-basis financials (not cash-basis)
Investors require accrual accounting. If your books are cash-basis, they'll ask for conversion — which takes 2–6 weeks and can pause the process.
24 months of monthly statements
P&L, balance sheet, and cash flow — every month for 24 months. Gaps in any month trigger questions about what happened that quarter.
Revenue recognized correctly (ASC 606)
Annual contracts recognized monthly. Setup fees deferred. Investors reconcile your reported ARR to your deferred revenue balance. A mismatch is a red flag — and the most common diligence surprise.
Clean chart of accounts
Expenses mapped to standard categories: COGS, R&D, S&M, G&A. Investors will reformat your financials to their template — clean COA makes this fast.
Bank accounts reconciled monthly
Every account, every month, to the penny. Unreconciled accounts signal weak financial controls and increase perceived risk.
Highest Risk Area 2: Revenue & ARR Quality
ARR/MRR waterfall reconciled to financials
New ARR, expansion, contraction, churn — all reconciling to recognized revenue and deferred revenue on the balance sheet. If your ARR schedule and balance sheet don't agree, diligence pauses.
Cohort-level MRR breakdown
Revenue by acquisition cohort (month started), showing expansion and churn by cohort over time. This is how investors calculate NRR — if you don't have it, they'll ask you to build it during diligence.
Customer concentration disclosure
ARR by customer for top 10 accounts. If your top 3 customers exceed 50% of ARR, expect detailed questions on contract terms and renewal risk.
Top 10 customer contracts
Actual executed contracts, not summaries. Investors check auto-renewal clauses, termination provisions, and whether any revenue can be easily clawed back.
High Risk Area 3: Unit Economics Verification
Fully-loaded CAC by channel
Investors recalculate CAC independently using your P&L S&M expenses. If your reported CAC excludes sales salaries, they'll find it. The correction typically makes LTV:CAC worse by 30–60%.
NRR verified from cohort data
Investors calculate NRR from the cohort waterfall. Common error: including new logo revenue in the numerator, which inflates NRR. If your reported NRR is 115% but cohort math says 95%, expect a repricing conversation.
Burn multiple independently calculated
Net burn from cash flow statement ÷ net new ARR from ARR waterfall. Investors do this calculation in their first model review. If it disagrees with your reported number, you have a credibility problem.
Gross margin by product line
COGS must include hosting, support, customer success (at least partially), and third-party software. Understated COGS = overstated gross margin = wrong LTV. Target ≥65% for SaaS. Source: OpenView Partners 2026 SaaS Benchmarks.
High Risk Area 4: Financial Model Integrity
Bottoms-up model (not top-down)
Revenue flows from headcount → pipeline → closed-won → ARR. "We'll grow 15% per month" is not a model. Investors stress-test assumptions against historical conversion rates.
Formula-driven (no hardcoded cells)
Investors run sensitivity analysis by changing growth rate assumptions. Hardcoded cells break this — and signal you don't understand the model yourself.
Actuals vs. model comparison
How has the model performed against actuals for the past 6 months? If you're consistently 40% off on growth, your model credibility collapses. Be ready to explain significant variances.
24-month model with three scenarios
Base, upside, downside — all using the same assumption structure with different growth inputs. Investors focus on the downside case: what happens if growth is 60% of your base projection?
Critical but Often Faster Area 5: Legal & Corporate
IP assignments — all founders and employees
Every person who built the product must have a signed IP assignment to the company. Missing assignment from a co-founder is a deal-stopper — not a fixable delay. This is the #1 legal deal-killer at Series A.
Delaware C-Corp incorporation
Series A investors require Delaware C-Corp. LLC or other state incorporations must convert — budget 4–6 weeks and $5K–$15K in legal fees if this isn't done.
Fully-diluted cap table
All shares, options (granted and ungranted), warrants, SAFEs, convertible notes — current and post-round pro forma. Investors reconcile this independently through their legal team.
Current 409A valuation (less than 12 months old)
Required to have issued options legally and to demonstrate clean option grant history. A stale 409A (or missing one) signals options may have been issued at incorrect strike prices.
The 6 Most Common Diligence Deal-Killers (2026)
#1
ARR doesn't reconcile to the balance sheet
Reported ARR vs. deferred revenue mismatch = revenue recognition error. Triggers accounting restatement or model rewrite.
#2
Understated CAC
Sales salaries excluded from CAC calculation. LTV:CAC collapses when investors recalculate. Repricing is almost automatic.
#3
NRR inflated by new logos
Including new customer revenue in NRR numerator. Actual NRR may be 30–40% lower. Signals weak retention.
#4
Missing IP assignments from a co-founder
Not fixable mid-diligence if the co-founder has left on bad terms. Deal-stopper.
#5
Cash-basis books
Conversion to accrual takes weeks. Investors often wait — or reprice the delay risk into the deal.
#6
Undisclosed customer concentration
Top 2 customers = 70% of ARR discovered mid-diligence. Creates negotiating leverage for investors to reprice on renewal risk.
Sources: Andreessen Horowitz (November 2025); Burkland Associates (February 2026); Sequoia Capital Arc (June 2025).
Series A Diligence Timeline
| Diligence Area | Typical Duration | Accelerated (Prepared) |
|---|---|---|
| Financial diligence | 2–4 weeks | 1–2 weeks (complete data room) |
| Legal diligence | 3–5 weeks | 2–3 weeks (clean docs) |
| Technical diligence | 1–2 weeks | 1 week |
| Customer references | 1–2 weeks | 1 week (references lined up) |
| Total (term sheet to close) | 6–10 weeks | 3–5 weeks |
Source: Sequoia Capital Arc (June 2025); Burkland Associates (February 2026).
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Frequently Asked Questions
What do Series A investors audit in financial due diligence?
Five areas: (1) books quality — 24 months accrual-basis financials; (2) revenue quality — ARR reconciled to deferred revenue; (3) unit economics — CAC/LTV/NRR independently calculated; (4) financial model integrity — bottoms-up, formula-driven; (5) legal — IP assignments, cap table, 409A. Most delays occur because of books quality or ARR reconciliation gaps. Source: Andreessen Horowitz (November 2025).
What causes Series A term sheets to be repriced or delayed?
Top causes: ARR doesn't reconcile to the balance sheet; understated CAC (sales salaries excluded); NRR inflated by including new logos; cash-basis books requiring conversion; missing IP assignments from a co-founder; undisclosed customer concentration. Each triggers repricing or significant delay. Source: Burkland Associates (February 2026).
How long does Series A financial due diligence take?
Financial diligence takes 2–4 weeks without a complete data room; 1–2 weeks with one. Total term sheet to close is 6–10 weeks typically; 3–5 weeks for prepared founders. The biggest time saver: having all 10 data room components complete before the term sheet is signed. Source: Sequoia Capital Arc (June 2025).
What should be in a Series A financial data room?
A complete data room contains: 24 months of monthly financial statements, MRR/ARR cohort waterfall, unit economics dashboard, 24-month three-scenario model, fully-diluted cap table + pro forma, top-10 customer contracts, IP assignments, 409A valuation, incorporation documents, and option plan with grants schedule. Source: Andreessen Horowitz (November 2025).
What financial model format do Series A investors expect?
A bottoms-up model (revenue from pipeline and conversion rates, not top-down percentages), formula-driven with no hardcoded cells, covering 24 months post-round with three scenarios, including a headcount plan and use-of-proceeds breakdown. Investors run sensitivity analysis — hardcoded models signal you don't control your assumptions. Source: First Round Capital (September 2025).