The story every founder tells eventually
A founder I know closed a Series A term sheet last spring with a top-tier fund. Clean process, warm intro, strong terms. Everyone was excited. Two weeks into diligence, the investor's lawyer sent over a list of cap table issues. Fifteen items. Three missing 83(b) elections from the founding team. A former co-founder still holding 8% of the company who was supposed to be bought out three years ago. Two option grants issued without board approval. Vesting start dates that didn't match the founder agreements.
What was supposed to be a four-week close became a five-month legal cleanup. The former co-founder had moved to another country and wouldn't return emails. The 83(b) issues required amended tax returns and CPA letters. The board consent packets had to be reconstructed retroactively. By the time everything was clean, the market had shifted, the investor's enthusiasm had cooled, and the round closed at a lower valuation than the original term sheet.
The deal didn't die. The momentum did. And it's the most common story in Series A diligence.
Why cap table cleanup takes longer than founders think
Cap table problems compound. A single missing signature from three years ago can require getting a former employee to sign paperwork. Each item cascades into more paperwork, more legal review, and coordination with third parties who may not have any reason to cooperate quickly.
What looks like a 20-minute fix from the outside — "just get the missing consent" — becomes a two-week hunt for a former co-founder who's now working at Google and doesn't return your emails. Multiply that across 15 issues and you have a five-month timeline.
Investors don't need perfection. They need documentation. Every share issued, every option granted, every vesting change, every transfer must have supporting paperwork that a lawyer can review and verify. Missing paperwork isn't a killer — it's an expensive slowdown that erodes momentum, valuation leverage, and investor conviction.
Here are the ten mistakes that show up most often in Series A diligence.
1. Missing 83(b) elections
The single most common cap table problem in Series A diligence. Founders and early employees who received restricted stock had 30 days from the grant date to file an 83(b) election with the IRS. Miss the window and the tax treatment on vesting equity gets significantly worse — each vesting event becomes a taxable moment on shares whose value has grown over time.
The 30-day deadline is absolute. There are no extensions, no hardship exceptions, no backdating. If it wasn't filed, it wasn't filed. Fixes exist but they're expensive and take months — amended returns, restructuring the grant, or in some cases restarting vesting from a later date.
Diligence lawyers ask for proof of 83(b) filing for every founder and every early exerciser. Missing filings surface immediately.
2. Unassigned pre-incorporation IP
Founders who wrote code, designed products, or built prototypes before incorporating the company technically owned that IP as individuals. Without a formal IP assignment agreement transferring ownership to the company at incorporation, the company doesn't legally own its own product.
This surfaces in every Series A diligence and can require executing assignment agreements years after the fact — sometimes with former team members who have no incentive to sign anything. Fix it at incorporation. It costs $500 in legal fees then and $25,000 in legal fees later.
3. Undocumented equity grants
Verbal promises. Slack messages. "You'll get some stock, don't worry about the paperwork right now." Every founder has done this. Every founder regrets it.
Every equity grant — to founders, employees, advisors, contractors — needs three things: board approval documented in a board consent, a signed stock or option purchase agreement, and updated cap table records. Missing any one of those three creates a diligence problem that can take weeks to unwind.
If someone claims they were promised equity and there's no paperwork, that claim becomes a legal exposure the acquirer or investor has to resolve before closing.
4. Former co-founders still on the cap table
A co-founder who left the company two years ago but was never formally bought out or terminated is a landmine. Their shares may still be vesting. They may have claims to future equity. Their signature may be required on documents they have no incentive to sign.
Every co-founder departure requires paperwork: termination of the stock purchase agreement, buyback of unvested shares, release of claims, updated cap table. If any of these were skipped or done informally, diligence surfaces the gap.
Fix departures at the moment they happen. Cleanup years later is dramatically harder.
Investors don't need perfection. They need documentation. Missing paperwork isn't a killer — it's an expensive slowdown that erodes momentum.
5. Vesting schedules that don't match reality
Vesting start dates that don't match when the founder actually started working. Cliff dates that were extended informally without paperwork. Accelerated vesting granted verbally after an acquisition offer that never happened. Every discrepancy between the vesting schedule on the cap table and the underlying documents is a diligence flag.
Fix them proactively. Every founder and employee should be able to say "my vesting started on X date, my cliff was Y date, and I've vested Z shares to date" and have documents that support every part of that statement.
6. Option grants without board consent
Every option grant to every employee requires board approval. Not verbal approval. Not "we'll sign it later." A formal board consent, signed by all directors, memorializing the grant date, share count, strike price, and vesting schedule.
Companies often issue grants and get board consent later, sometimes months later. The problem: the strike price is set by the 409A valuation on the grant date, and delayed approval can invalidate the grant or trigger 409A violations. Fix your board consent cadence. Grants get approved before employees start vesting, not after.
7. Stale 409A valuation
The 409A sets your option strike price. It expires 12 months after issuance or when a "material event" occurs — a new funding round, significant business change, or exit event. Issuing options against an expired 409A creates real tax exposure and diligence problems.
Refresh the 409A every 12 months and immediately after any material event. Budget for it as a recurring cost — typically $2,000-$5,000 per valuation.
8. SAFE terms that don't add up
Multiple SAFEs at different caps, different discounts, different pro-rata rights. Some with MFN clauses. Some with side letters. Some documented on the cap table with terms that don't match the underlying SAFE documents.
Diligence lawyers model every SAFE's conversion in every scenario. If your cap table shows one conversion outcome and the SAFE docs support a different one, you have a problem. Reconcile every SAFE against the underlying documents before starting a Series A process.
9. Founder shares never actually issued
The most subtle mistake. Founder shares require a board resolution authorizing the issuance, a stock purchase agreement, payment of the purchase price (even if it's $0.0001 per share), and delivery of the stock certificate or entry in the stock ledger. Skip any one of these and the shares may not have been legally issued at all.
Diligence lawyers verify every founder's shares against these four elements. Missing pieces require reconstructive paperwork that can require getting current signatures on documents backdated to the incorporation date — a legally and ethically fraught process.
10. Cap table software that doesn't match reality
Carta, Pulley, and other cap table platforms only reflect what you tell them. If your Carta records show 10,000 vested options for an employee but the underlying stock ledger shows 8,000 exercised and 2,000 canceled, you have a discrepancy that surfaces immediately in diligence.
Reconcile your cap table software against the underlying documents at least quarterly. Whenever anything changes — grants, exercises, terminations, transfers — update both the software and the source documents at the same time.
What to do about it
Four concrete actions before starting any Series A process:
Do a cap table audit 6-12 months before you plan to raise. Every share, every grant, every transfer. Check every 83(b) election. Check every board consent. Check every stock purchase agreement. Fix what's broken while you have time and leverage.
Migrate to a proper cap table platform if you haven't. Carta or Pulley for $300-$2,000/year is trivial against your burn rate and prevents the kinds of reconciliation errors that surface in diligence.
Bring in your startup lawyer for a pre-diligence review. They know what Series A lawyers look for. A four-hour review with them costs $2,000-$4,000 and can prevent $50,000 in cleanup later.
Never let paperwork slip in the moment. Every grant, every departure, every material change gets documented at the time it happens. Not later. Not "we'll clean it up." At the time.
The takeaway
Cap table mistakes rarely kill Series A deals outright. But they slow them down, weaken the founder's leverage, and give investors reasons to renegotiate terms mid-process. The founders who close cleanly are the ones who arrive at diligence with documentation that a lawyer can verify in hours, not weeks.
Fix your cap table before you need it. Your Series A closes faster, closes at better terms, and closes with the investor's conviction intact. The alternative — a five-month legal cleanup with a fading term sheet in your hand — is entirely avoidable and entirely too common.
Want to stress-test your cap table against real diligence scenarios? Try the Cap Tables topic pack on Gargiulo — ten scenarios covering everything in this guide plus the deeper mechanics of dilution, share classes, and cap table math. Sterling has spreadsheets.
Sources: CRV, Bowery Legal, Baker Tax Law, The Startup Law Blog, Crowley Law, and analysis from Cooley GO term sheet database.