Incorporating has never been easier — an afternoon on Firstbase, Stripe Atlas, or Clerky and you have a Delaware C-Corp, an EIN on the way, and a bank account application in progress. What nobody hands you at the end of that afternoon is the tax clock that started the same day. Some of the deadlines below are forgiving. One of them is not.
The 83(b) election — 30 days, no extensions
If you or your co-founders received stock subject to vesting, the 83(b) election is the one deadline in this article with no second chance: 30 days from the date the stock is transferred to you, with no relief if you miss it. For founder stock bought under a stock purchase agreement, that clock generally starts on the purchase or transfer date — not the day the board approved the grant, which can be earlier. Filing means you're taxed on the stock's fair market value at transfer — often minimal at formation, though that depends on your actual facts — instead of at each vesting date, when a rising valuation can turn vesting itself into a tax bill on money you never received.
If your stock was issued through a cap table platform like Carta or Pulley, check what 83(b) support it offers. Either way, the IRS now accepts the election on Form 15620, including online through its portal — our box-by-box walkthrough explains every field. The IRS filing isn't the only step: the regulations also require providing a copy to the company that issued the stock. If you'd rather see exactly what you're sending, our free 83(b) election letter template generates the full filing text — no signup required.
The Delaware franchise tax scare
Sometime in your first year, Delaware will remind you that the corporation's annual franchise tax is due March 1. If your company authorized the standard ten million shares, the authorized-share method — the default calculation on the notice — can produce a surprisingly large bill. Delaware also permits corporations to calculate the tax using the assumed par value capital method, which takes into account issued shares and the company's total assets. For many early-stage companies this results in a substantially lower bill, often near the minimum — though the actual amount depends on your capitalization and assets, and the minimum and rates should be checked for the specific tax year. The annual report and the franchise tax are distinct obligations, generally handled in the same filing on the Delaware Division of Corporations site; if you incorporated through a service like Firstbase, check whether your plan covers this filing. The big number on the notice is a default calculation, not a verdict.
Federal filings exist even at zero revenue
- C-Corp Form 1120 is due April 15 for a calendar-year corporation (extendable to October 15 with Form 7004) — even for a year with no revenue at all. A no-activity year is a short return, but skipping it starts penalty clocks.
- Accidental partnership Started with a co-founder as a multi-member LLC and never elected anything? By default that's a partnership: Form 1065, due March 15, with a per-partner, per-month late-filing penalty that stings precisely because nobody knew a return was due.
- S-Corp election Form 2553 is due within 2 months and 15 days of the start of the tax year it should take effect. If the deadline is missed, late-election relief may be available under Rev. Proc. 2013-30 if the corporation meets the applicable requirements — the request must include the required representations and filing statements. Our late S election relief template drafts that request.
- Foreign founders A foreign-owned U.S. disregarded entity — typically a single-member LLC with a foreign owner — must file Form 5472, attached to a pro forma Form 1120, for a year in which it has reportable transactions with a related party. Even the owner's own contributions to the LLC can be reportable, which is how a company with no revenue ends up with this filing; whether it's required in a given year depends on the entity's classification, ownership, and transactions. When it is required and missed, the penalty is $25,000 — with further penalties if the failure continues after the IRS makes contact.
Your incorporation state isn't where you owe taxes
Delaware is where the company lives on paper — not necessarily where it owes taxes. State obligations depend on where the company actually has activity: employees, property, sales, and the other contacts states call "nexus," with the rules differing by state and by tax type. A company doing business in another state generally also needs to register there ("foreign qualification") — a legal requirement that turns on whether its activities amount to doing business under that state's law, not one automatically triggered by a single remote worker or sale. The common case: a Delaware corporation doing business in California may have California registration, tax, and filing obligations, depending on its activities. When you're comparing what two states actually demand, our State Tax Matrix puts their income tax and sales & use tax rules side by side, cited to each state's own authority.
The first-year calendar
| Obligation | Deadline | Where founders handle it |
|---|---|---|
| EIN application + tax-year determination | At formation — your first federal return depends on the actual tax year and start date | IRS (Form SS-4, online); check whether your incorporation service includes it |
| 83(b) election | A specific date: your stock transfer date + 30 days — no extensions | IRS Form 15620; your cap table platform (Carta / Pulley); free template on Taxflows |
| Delaware franchise tax + annual report | March 1 | corp.delaware.gov, or your incorporation service's compliance package |
| Form 1065 (multi-member LLC default) | March 15 | Your accountant or tax preparer |
| S-Corp election (Form 2553) | 2 months + 15 days into the tax year | IRS; late relief may be available under Rev. Proc. 2013-30 |
| Form 1120 (C-Corp) | April 15 (calendar year) | Your accountant or tax preparer |
| Payroll + employment registrations | When you hire — withholding, unemployment, and related obligations | State agencies; usually set up through your payroll provider |
| State registration where you operate | When your activities amount to doing business there | State agencies; compare states on the State Tax Matrix |
When to ask, not guess
Every item above has edge cases the checklist can't hold — a QSBS question at your first fundraise, a contractor in a second state, a fiscal year that isn't the calendar year. That's what the AI Tax Assistant is for: ask in plain English, get an answer cited to the Code, the regulations, and state guidance, and verify the source in one click. The free tier needs no credit card — and the entity facts you enter once are remembered for every question after.
Shashank Sharma is the founder of Partnertax.ai, an AI tax assistant for tax professionals, built on cited IRS and Treasury sources.