Spread

What Is the Spread?

The spread — also known as the bargain element — is the difference between the current fair market value (FMV) of a share of stock and the exercise price (strike price) of your stock option. If your strike price is $2 per share and the current FMV is $10, your spread is $8 per share. The spread represents the built-in, unrealized gain in your stock options and is the primary driver of both the financial value and the tax consequences of exercising.

The spread is sometimes referred to interchangeably with the "bargain element," though technically the bargain element is the spread measured specifically at the time of exercise. In practice, the terms are used synonymously.

How the Spread Works

Calculating the Spread

The formula is straightforward:

Spread = Current Fair Market Value − Exercise Price

For private companies, the current FMV is determined by the most recent 409A valuation. For public companies, it is the current market price. The exercise price is fixed at the time of grant and does not change.

The Spread Changes Over Time

Unlike the exercise price (which is locked in), the fair market value changes as the company's valuation evolves. If the company grows, the FMV increases and the spread widens. If the company's value declines (perhaps due to a down round), the FMV may fall closer to — or even below — the exercise price, shrinking the spread to zero or making the options "underwater."

Spread and Tax Consequences

The spread at the time of exercise determines your tax liability:

For NSOs: The spread is taxed as ordinary income in the year of exercise, subject to federal income tax, state income tax, and payroll taxes (Social Security and Medicare). Your employer withholds taxes just as they would on salary.

For ISOs: The spread is not subject to regular income tax at exercise. However, it is an adjustment for the Alternative Minimum Tax (AMT). If the spread is large enough, it can trigger a significant AMT liability. The spread is also relevant later — if you make a qualifying disposition, the entire gain from exercise price to sale price is taxed at long-term capital gains rates. If you make a disqualifying disposition, the spread at exercise is reclassified as ordinary income.

Spread vs. Gain at Sale

The spread at exercise and the gain at sale are different. If you exercise at a $2 strike price when the FMV is $10 (spread = $8), and later sell when the market price is $15, your total gain per share is $13. But the tax treatment of that $13 gain may be split: $8 treated one way (based on option type and holding period) and $5 treated as capital gain.

Practical Implications for Startup Employees

A Large Spread Means a Large Tax Bill

If you have been at a company for several years and the 409A valuation has increased significantly, the spread at exercise can be substantial. Exercising 10,000 ISOs with a $20 spread creates a $200,000 AMT adjustment. For NSOs, that same spread creates $200,000 of ordinary income. Before exercising, calculate the spread and model the resulting tax liability.

Exercise Early When the Spread Is Small

One of the most effective tax strategies is to exercise when the spread is small — ideally near zero. If you exercise shortly after your grant date when the FMV equals or is close to your strike price, the spread is minimal, the tax consequences are negligible, and you start your holding period clocks immediately. This is the logic behind early exercise strategies and 83(b) elections.

Monitor the 409A Valuation

The 409A valuation determines the FMV used to calculate your spread. Track when your company gets new 409A valuations — they typically occur every 12 months or after a material event like a funding round. If a funding round is approaching, exercising before the new (higher) 409A valuation locks in a smaller spread and a smaller tax bill.

How It Relates to Exercising Stock Options

The spread is the central variable in every exercise decision. It determines how much tax you will owe, what kind of tax you will owe, and whether exercising makes financial sense at the current moment. A small spread means lower taxes and more flexibility. A large spread means a larger potential gain but also a larger tax bill. Use your company's current 409A valuation and your option agreement's strike price to calculate the spread before making any exercise decision.