In our view, the most common startup legal mistakes are skipping a founder agreement, leaving IP outside the company, choosing the wrong entity, misclassifying workers, promising equity on a handshake, missing the 83(b) deadline and ignoring securities rules when raising. Each tends to be cheap to prevent and expensive to fix, and many surface in investor due diligence.
The full list of ten adds a drifting cap table, founder stock without vesting and DIY contracts for high-stakes deals. None of these feels urgent the day it happens. That's the problem.
Below, each mistake comes with why it happens and one way to fix it, followed by a prevention checklist you can work through in a weekend. Your own lawyer's advice should take priority over any general list like this one.
Why startup legal mistakes are so expensive
Early legal work has an unusual cost curve. Doing it well is relatively cheap and fixed. The cost of getting it wrong tends to grow with your success.
A missing IP assignment from a departed co-founder matters little if the company fails. It can become a deal-breaker when you are raising a $3M seed round.
Investors know this. A typical seed due diligence checklist often asks for your charter, board consents, stock purchase agreements, IP assignments, cap table and contractor agreements. Gaps can slow the close and shift leverage to the investor, who may then have a reason to ask for a lower valuation, a special indemnity or a cleanup condition before funding. It's also why we tend to read the cap table before the deck (our take on why).
The 10 most common startup legal mistakes
1. No founder agreement
Two or three people start building. Nobody writes down who owns what or what happens if someone leaves. Six months later one person is doing most of the work and the split is still "equal, I guess."
Fix: many founders sign a founder agreement at or shortly after incorporation, covering equity split, vesting, roles, decision rights, IP and departures. Our guide on why founder agreements matter covers the essential clauses.
2. No intellectual property assignment
The company does not automatically own the code, designs or brand you created before incorporation, or work a contractor created for you. Absent a written assignment (or, for employees, work made within the scope of employment), the creator may own it.
Fix: a common approach is for every founder to sign an IP assignment at incorporation covering pre-formation work, and for every employee and contractor to sign a confidentiality and invention assignment agreement before starting.
Your name is IP too. The USPTO notes that one of the most common reasons trademark applications are rejected is similarity to an existing registered mark, so take the time to search for similar trademarks before you invest in a brand.
3. The wrong entity
An LLC can suit a consulting firm or a bootstrapped company that does not plan to raise venture capital. It is often a poor fit for a startup that plans to raise from angels or funds, grant stock options or issue SAFEs. Cooley GO notes that many venture funds cannot invest in LLCs for tax reasons, and that incentive stock options are only available to corporations.
Fix: if you plan to raise outside capital or grant equity to employees, many advisers suggest a Delaware C corp from the start. If you already have an LLC, converting is routine but costs time and legal fees. Our guide on how to incorporate your startup is a reasonable place to start before you file anything.
4. Misclassified workers
Treating a full-time, directed, long-term worker as a 1099 contractor saves payroll taxes now and creates back-tax, penalty and benefits exposure later. The IRS looks at three categories of evidence under its common-law rules: behavioral control, financial control and the type of relationship. Some states apply stricter tests of their own, such as California's ABC test, which presumes a worker is an employee unless the hiring business proves all three of its conditions.
Fix: apply the tests honestly. If you set their hours, direct how they work and they work only for you, they are probably an employee. When in doubt, put them on payroll, restructure the engagement so it is genuinely project-based, or ask counsel. The IRS will issue a formal determination on Form SS-8, but it warns that a determination may take at least six months.
5. Handshake equity
"You'll get 2 percent when we raise" is a common sentence in early startups. We'd call it a risky one. Verbal equity promises are vague, hard to value and often remembered differently by each side.
Fix: put every equity promise into a signed document: a stock purchase agreement, an option grant under a board-adopted plan, or an advisor agreement with a specific share count and vesting schedule. Consider pricing options off a current 409A valuation. Carta warns that a below-market strike price can trigger significant tax penalties for employees, and that the IRS safe harbor needs a new 409A every 12 months or after a material event.
6. Missing the 83(b) election
Section 83(b) of the Internal Revenue Code lets you elect to be taxed on restricted stock when you receive it rather than as it vests. Under the statute, the election must be made no later than 30 days after the date the stock is transferred to you, and that deadline is fixed.
For founders buying shares at a tiny price, filing usually means little or no tax now. Missing it can mean ordinary income tax on the spread at each vesting date as the company's value rises.
Fix: many founders file the election the same week they sign the stock purchase agreement, follow the IRS's current filing instructions, keep proof of timely filing and store a copy with their records. Since July 2025 the IRS has accepted elections online on Form 15620 through an IRS online account, and mail (traditionally certified, with a return receipt) remains an option, as Goodwin's July 2025 alert explains. We'd treat this as a founder-level task, not something to delegate and forget.
7. Ignoring securities rules when raising
Under federal securities law, when you sell stock, a SAFE or a convertible note, you are selling a security and need an exemption from registration. Most startups use Regulation D.
Under Rule 506(b), you cannot use general solicitation, and you may sell to no more than 35 non-accredited investors, who must be financially sophisticated (alone or with a purchaser representative) and receive extensive disclosure. Under Rule 506(c), you may advertise publicly, but the rule requires every purchaser to be accredited and requires you to take reasonable steps to verify that status. Either way, the SEC requires a Form D notice within 15 days after the first sale (the date the first investor is irrevocably committed), and states can require their own notice filings and fees.
Fix: a common approach is to raise from accredited investors under a standard exemption, keep records of accreditation, and have counsel handle the federal and state filings after each close. Treat "we are raising" posts on social media as a question for your lawyer, because public promotion can take 506(b) off the table. The 506(b) vs. 506(c) and blue sky laws guides explain the mechanics.
8. A sloppy cap table
Founders often track ownership in a spreadsheet that does not match the signed documents. SAFEs get forgotten, option grants are approved verbally, and share counts drift. By the seed round, nobody may know the fully diluted picture.
Fix: keep one master record, reconcile it to signed documents every quarter, and model your SAFEs before signing new ones so you know what converts at what price. See cap table management for startups for a working setup.
9. No vesting on founder stock
If a co-founder leaves after four months with 40 percent of the company fully vested, you have a dead-weight shareholder, a frustrated team and a cap table investors may hesitate to fund.
Fix: the common market structure is four-year vesting with a one-year cliff and monthly vesting after that. Investors often require founder vesting at the first priced round anyway, so setting it yourself removes the negotiation later. It is usually paired with a timely 83(b) election; our guide to founder vesting and the 83(b) election shows how the two work together.
10. DIY contracts for things that matter
Templates are often fine for a simple NDA. They can be risky for customer agreements with liability caps, enterprise data terms, key hires and anything involving equity. One poorly drafted limitation-of-liability clause can leave a company exposed to damages far beyond the contract's value.
Fix: use vetted templates for routine documents and a startup lawyer for the ones that carry real risk. Our guide to choosing a startup lawyer explains how to budget.
"We'll clean it up before we raise"
It's a common plan, and it isn't crazy. Early on, cash is scarce, the product matters more, and some of these issues may not matter at all if the company doesn't work.
But Cleanup gets harder the longer you wait. The co-founder who needs to sign an IP assignment may have left on bad terms. The contractor may be unreachable. A missed 83(b) deadline generally can't be fixed later. We'd do the cheap, time-sensitive items now (vesting, IP, 83(b), equity paperwork) and leave the rest for when it matters. It's the same point we've made about settling equity before you fundraise.
What clean startup legal work typically costs
Legal pricing varies widely by firm, city and complexity, so treat these as rough ranges, not quotes:
| Item | Rough cost range | When |
|---|---|---|
| Delaware C corp formation with founder docs | Low thousands of dollars | At incorporation |
| Equity incentive plan and first grants | Low to mid thousands | Before first hire |
| SAFE round documentation | Low thousands, more if terms are negotiated | At the raise |
| Fixing a missing IP assignment or vesting problem | Often more than prevention would have cost | Usually in diligence |
Many startup firms offer fixed-fee formation packages or deferred billing, so ask. Doing the work up front is usually cheaper than cleanup, and cleanup also costs you time and leverage.
Startup legal rules that changed recently
Two federal changes affect what early-stage founders need to do, and older advice online still gets both wrong.
Beneficial ownership (BOI) reports. US startups were once told to file BOI reports under the Corporate Transparency Act. According to FinCEN, all entities created in the United States were exempted in March 2025, and a final rule effective August 14, 2026 made that permanent. Foreign companies registered to do business in a US state still report, but not the ownership of US persons.
Verifying accredited investors under Rule 506(c). In a March 2025 no-action letter, SEC staff agreed that a high minimum investment (the request proposed $200,000 for individuals and $1 million for entities) plus written representations of accredited status and no third-party financing can be reasonable verification, absent contrary knowledge. It helps with large checks, not small angel checks.
Prevention checklist: the startup legal hygiene audit
Work through this once, then review it every six months. Adapt it with your counsel.
- Delaware C corp formed, with bylaws, initial board consent and stock ledger.
- Founder agreement signed and consistent with the stock purchase agreements.
- Founder stock issued with vesting (commonly four years with a one-year cliff).
- 83(b) elections filed within 30 days of each stock transfer, with proof of filing kept.
- IP assignments signed by every founder, covering pre-formation work.
- Confidentiality and invention assignment agreements for every employee and contractor.
- Worker classification reviewed against the IRS common-law factors and your state's test.
- Equity incentive plan adopted by the board before the first grant; every grant approved by board consent at a strike price backed by a current 409A valuation.
- Cap table reconciled to signed documents, including all SAFEs and notes.
- Securities exemption documented, Form D filed within 15 days of first sale, and state notice filings made.
- Customer, vendor and partner contracts reviewed by counsel where liability or data is involved.
- Board resolutions and consents stored in one organized folder.
With all twelve in place, diligence is much more likely to feel routine than like a fire drill.
Where 1752vc fits
Many of these mistakes come from founders not knowing what "investor-ready" looks like until an investor tells them. Ignite, 1752vc's startup academy for first-time founders in the early stages, is one way to close that gap sooner: a 12-week program, live and remote, that founders work through at their own pace while the company is still being built, well before a first raise puts its legal and equity foundations through diligence. If you are still validating the idea, Launchpad is a 12-week, self-paced sprint that helps aspiring founders go from -1 to 1 before the legal stakes rise.
The bottom line
None of these mistakes is exotic. They're ordinary, cheap to prevent, and easy to put off, which is exactly why they show up in diligence.
A weekend of paperwork now is cheap.
A week of cleanup mid-raise is not.
Key takeaways
- The legal mistakes startups make tend to be cheap to prevent and expensive to fix, and many surface during fundraising diligence.
- A founder agreement, IP assigned to the company and vesting on founder stock are, in our view, the foundations worth getting right first.
- The statute gives you 30 days after receiving restricted stock to file an 83(b) election, and that deadline does not move.
- It helps to put every equity promise in writing under a board-adopted plan and reconcile the cap table to signed documents quarterly.
- Under SEC rules, a fundraise is a securities offering: most startups rely on a Regulation D exemption, file Form D within 15 days of the first sale, and handle state notice filings.
Frequently asked questions
The ones most often cited are skipping a founder agreement, failing to assign IP to the company, choosing an LLC when planning to raise venture capital, misclassifying workers, promising equity verbally and missing the 83(b) election. Sloppy cap tables, no founder vesting, ignored securities rules and DIY contracts round out the list.
You can form the entity yourself or through an online service, but we would have a startup lawyer handle founder stock, IP assignments, the equity plan and any fundraising documents. Legal costs vary widely by firm and city, and many startup firms offer fixed-fee formation packages or deferred billing. Paying for those documents up front is usually far cheaper than cleaning up problems during diligence.
The 30-day deadline is set by statute, and practitioners generally say there is no way to file late. Without the election, you will typically owe ordinary income tax on the value of each tranche as it vests, which can be a large bill if the company's value rises. Many founders file the same week they sign their stock purchase agreement.
Only if your offering allows general solicitation. Under Rule 506(c) you may advertise, but the rule requires every investor to be accredited and requires reasonable steps to verify it. Under Rule 506(b), general solicitation is not allowed, so a public "we are raising" post can cost you that exemption. It is worth checking with counsel before posting anything about a live round.
Not if the company was formed in the United States. FinCEN exempted all US-created entities from beneficial ownership reporting in March 2025, and a final rule effective August 14, 2026 made that permanent. Foreign companies registered to do business in a US state still have to report, although they no longer report US persons as beneficial owners.
If you plan to raise from angels or venture funds, grant stock options or use SAFEs, a Delaware C corporation is the standard expectation, partly because many venture funds cannot hold LLC interests. An LLC can work for bootstrapped or service businesses that will not take outside equity. Converting later is possible but adds legal cost and delay.
Sources
- Cornell Law School LII: 26 U.S. Code Section 83
- FinCEN: Beneficial Ownership Information Reporting
- Cooley GO: Choosing the Correct Business Entity, The Basics
- Carta: Issuing Options, 5 Common Mistakes to Avoid
- IRS: Independent Contractor (Self-Employed) or Employee?
- SEC: Private Placements, Rule 506(b)
- SEC: General Solicitation, Rule 506(c)
- SEC: Filing a Form D Notice
Disclaimer: This guide is for general education only and is not legal, tax or investment advice. Laws, market data and program terms change, so it may not reflect the latest developments or fit your situation. Treat it as a starting point, not a source of truth, and talk to a qualified lawyer, accountant or financial adviser before you make decisions.
