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Operator guideAt incorporation, founders typically purchase stock at par value subject to vesting. Three companion documents matter: the Stock Purchase Agreement, the IP Assignment, and the 83(b) election.
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Founder Stock Purchase Agreement Guide · File.Business

Founder stock purchase agreement. Vesting + IP + 83(b).

The Founder Stock Purchase Agreement is the foundational equity document for a C-Corp. Founders purchase stock at incorporation (typically at par value), subject to vesting and Company's right to repurchase unvested shares if the founder leaves. This guide walks through what to include, the 83(b) timing, and common mistakes.

Key facts

Start here.

Key fact
Purchase at par

Typically $0.0001/share. Near-zero cost for founder.

Key fact
Vesting

Standard 4 years with 1-year cliff. 25% vest at year 1; monthly thereafter.

Key fact
Repurchase right

Company may repurchase unvested shares at original price upon termination.

Key fact
IP assignment

Founder assigns all pre-existing IP related to business.

Key fact
83(b)

File within 30 days of stock issuance.

In depth

The full picture.

01

Structure of Founder Stock Purchase Agreement

Parties: Corporation and Founder. Identification of stock: number of shares, class (Common Stock typical), price per share (par value: $0.0001 typical). Total purchase price: number of shares × price (e.g., 1,000,000 shares × $0.0001 = $100).

02

Vesting Schedule

4-year vesting with 1-year cliff is standard. 25% of total shares vest at the first anniversary of the vesting start date. Remaining 75% vest monthly over the next 36 months (1/48th per month). Vesting start date often the incorporation date or earlier (if pre-incorporation work).

03

Repurchase Right

Company has the right to repurchase unvested shares at the original purchase price upon Founder's termination of service (for any reason, including death, disability, voluntary departure, termination for cause). Repurchase is typically within 90-180 days of termination.

04

IP Assignment

Built into the agreement or separate IP Assignment. Founder assigns to Company all IP related to the business: prior code, designs, ideas, inventions. Future IP made during engagement automatically assigned.

05

83(b) Election Acknowledgment

Agreement includes notice to Founder of 83(b) election option and 30-day filing requirement. Founder acknowledges receipt and responsibility to file independently with IRS.

06

Acceleration Provisions (optional)

Some agreements include acceleration on certain events. Single trigger: acquisition alone (unusual). Double trigger: acquisition AND termination without cause within 12-24 months post-close (standard for senior executives and some founders). Negotiable.

07

Confidentiality + Non-Solicitation

Standard provisions. Founder maintains confidentiality of Company information during and after service. Time-limited non-solicit of customers and employees (often 12 months post-termination).

08

Representations

Founder represents: authority to enter; no conflicts with prior employer agreements; accurate disclosure of prior IP retained; full and accurate information.

09

Common Mistakes

Skipping IP Assignment. Missing 83(b) deadline. Not setting vesting (investors require). Inconsistent vesting dates across co-founders. Unclear acceleration provisions.

FAQ

Common questions.

What is a founder stock purchase agreement?
A founder stock purchase agreement is the document under which a founder acquires their shares in the startup, typically subject to vesting, so it sets how and when the founder earns their equity. It is foundational to a startup's cap table. We keep your cap table organized around it.
Why do founders buy their stock?
Founders typically purchase their shares, often at a nominal price early, so ownership is properly issued and documented, which, combined with vesting, sets up a clean equity structure investors expect. We flag how founder stock is issued so your ownership rests on proper documentation.
Why is vesting in the agreement?
Vesting, commonly four years with a one-year cliff, means founders earn their stock over time, protecting the company if a founder leaves early and reassuring investors. We flag how vesting is built into the agreement so your equity structure is what investors expect.
What is the 83(b) election here?
When founder stock is subject to vesting, an 83(b) election lets the founder pay tax on the low value at grant rather than as it vests, but it must be filed with the IRS within 30 days. We flag this deadline so it is not missed, since a late 83(b) cannot be made.
What happens to unvested founder stock if someone leaves?
Unvested shares are typically subject to repurchase by the company when a founder leaves, returning them to the pool, while vested shares are kept, which is the protection vesting provides. We flag how departures affect the cap table so the mechanics are clear before they happen.
How does founder stock affect the cap table?
It establishes founders' ownership and, with vesting, how much is earned over time, so it is a foundational line on the cap table that investors examine. We keep your cap table organized so founder ownership and vesting are accurately reflected and investor-ready.
Do all founders need one?
Generally yes: each founder should have a stock purchase agreement with vesting so ownership is properly issued and the company is protected if a founder departs, which investors expect across the founding team. We flag this so every founder's equity is documented consistently.
When should founder stock be set up?
Early, when the company is formed and the stock has low value, since that is when purchase and the 83(b) election are cleanest and the tax cost lowest. We flag the timing so founder stock and the 83(b) window are handled at formation rather than missed later.
Can File.Business help with founder equity?
We form the corporation, set up the cap table, and flag the founder stock, vesting, and 83(b) considerations, coordinating with your counsel on the agreements, so your founding equity is issued and documented correctly from the start.

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