What it calculates

Stock-based compensation expense measures the cost of paying employees in equity. It is a real expense even though no cash leaves the company - the cost is borne by existing shareholders through dilution - and it is recognised over the period the employee earns the award.

How it is calculated

Awards are measured at fair value on the grant date and that value is fixed regardless of later share price moves. Restricted stock units are valued at the share price on grant. Options are valued with Black-Scholes or a lattice model, using expected volatility, expected term, the risk-free rate and dividend yield. The grant-date value is then recognised over the vesting period, either straight line for cliff vesting or by tranche for graded vesting, with forfeitures either estimated up front or recognised as they occur.

How to read the result

Because the expense is locked at grant, it tells you nothing about the current value of the awards - a heavily underwater option still generates expense every quarter. The number that matters for shareholders is dilution, not the P&L charge, so track shares outstanding and the unvested pool alongside the expense. Watch the unrecognised compensation cost disclosed in the notes: it is the committed future expense already granted and not yet recognised, and it tells you what the run rate will be.

Worked example

50,000 RSUs granted at a 40.00 share price is 2,000,000 of total cost. With four-year straight-line vesting, that is 500,000 a year, or 125,000 a quarter. If 10% are forfeited in year two, cumulative expense is trued up so only the value of awards expected to vest is recognised.

Common questions

Is stock compensation a real expense?

Yes. Paying someone in equity instead of cash transfers value from existing shareholders to the employee. Excluding it from adjusted earnings, which is common, treats employee pay as free - and is only defensible if you also account fully for the dilution it causes.

What is the difference between RSUs and options for accounting?

RSUs have intrinsic value at grant equal to the share price, so valuation is trivial and they retain value even if the share price falls. Options need an option-pricing model and expire worthless below the strike, so they carry more expense volatility in the assumptions and more risk for the employee.

What happens to the expense if the share price collapses?

Nothing. Grant-date fair value is not remeasured for equity-classified awards, so the expense continues even on options that will never be exercised. Only a modification, such as repricing, causes incremental expense to be recognised.