CFA Level II Exam · Employee Compensation: Post-Employment and Share-Based

Option Valuation Assumptions and Their Effect on Compensation Expense

Updated 7 October 2026 · Fact-checked

Option valuation assumptions are the inputs a pricing model uses to set the grant-date fair value of employee options: volatility, expected term, dividend yield and risk-free rate. Higher volatility and a longer term raise fair value and expense. To solve questions, find the inputs, judge their direction, compute expense over the vesting period, then check dilution.

Understand Option Valuation Assumptions and Analytical Implications

When a company grants employees stock options, it receives their services in return. Accounting treats that as a cost. Under IFRS 2 (and ASC 718 under US GAAP), equity-settled options are measured at grant-date fair value and expensed over the vesting period. The company does not remeasure that fair value later for equity-settled awards.

Fair value comes from an option pricing model, usually Black-Scholes-Merton or a binomial model. The model needs inputs: current share price, exercise price, expected term, expected volatility, expected dividend yield and the risk-free rate. Management chooses the expected term, volatility and dividend yield. That judgment is where earnings quality questions begin.

The direction of each input matters more than the arithmetic. For a call option, a higher share price, higher volatility, longer expected term and higher risk-free rate all raise fair value. A higher exercise price or higher dividend yield lowers it. Volatility and expected term are the two assumptions with the largest effect, and management has the most room to shade them. Lower volatility or a shorter term gives a lower expense and higher reported earnings, with no change in the economics of the grant.

Total expense is fair value times the number of options expected to vest, spread over the vesting period, usually straight-line. Management must estimate forfeitures and update that estimate. A change in the estimate triggers a cumulative catch-up in the period it changes.

As an analyst you do three things. First, compare assumptions across firms and over time, since a firm with much lower volatility than similar peers may understate expense. Second, assess dilution: options in the money raise diluted share count, normally through the treasury stock method. Third, judge earnings quality. Share-based pay is a real cost to shareholders even though it is non-cash. The indirect-method cash flow statement adds it back, and many non-GAAP measures exclude it. Disclosures in the notes (assumptions used, options outstanding, unrecognized cost) give you the data.

Key formulas to remember

Annual compensation expense (straight-line): Expense per year = Fair value per option × Options expected to vest ÷ Vesting period (years); Options expected to vest = options granted × (1 − expected forfeiture rate). Fair value is fixed at grant for equity-settled awards.
Cumulative catch-up on forfeiture revision: Period expense = Revised cumulative expense to date − Expense already recognized; Revised cumulative expense = fair value × revised options expected to vest × (years elapsed ÷ vesting period).
Treasury stock method (options): Incremental shares = Options × (1 − Exercise price ÷ Average market price); Applies only when options are in the money (average price above exercise price). Otherwise they are antidilutive and ignored.
Direction of inputs on call option fair value: ↑ Volatility, ↑ Expected term, ↑ Risk-free rate, ↑ Share price → ↑ value; ↑ Dividend yield, ↑ Exercise price → ↓ value; Use this to judge whether an assumption change raises or lowers reported expense.
Diluted EPS with options: Diluted EPS = Net income ÷ (Basic shares + Incremental shares from options); No preferred dividends or convertible adjustments in simple cases.

How to solve Option Valuation Assumptions and Analytical Implications questions

Use this sequence for any item-set question on option assumptions, expense or dilution.

1Read the vignette and exhibit for grant date, number of options, vesting period and type of award (equity-settled or cash-settled).
2List the model inputs given: volatility, expected term, dividend yield, risk-free rate, exercise price and share price.
3For a question about assumptions, decide the direction of each input on fair value, then on expense and net income.
4For an expense calculation, take fair value per option, multiply by options expected to vest after forfeitures, and divide by the vesting period.
5If the forfeiture estimate changes, compute revised cumulative expense to date and subtract what you already recognized.
6For dilution, check whether options are in the money, then apply the treasury stock method using average market price.
7Finish with the analyst judgment: compare assumptions with peers, note whether expense looks understated, and state the effect on earnings quality.

Quickest way: Direction-first shortcut

When to use it: Use it when the question asks which assumption is aggressive or how a change affects expense, with no calculation needed.

Ask whether the change raises or lowers option fair value, using the direction rule.
Lower fair value means lower expense and higher net income, so it is the aggressive choice.
Lower volatility, shorter expected term and higher dividend yield are the aggressive ones for calls. A lower risk-free rate would also lower value, but it is observable and not a management judgment, so it is not usually a red flag.
Compare with peers or prior years. A firm far below peers with similar business and stock behavior is the red flag.
For numeric items, compute expense per year first, then adjust only for the change given.

Common mistakes in Option Valuation Assumptions and Analytical Implications

Remeasuring equity-settled options at each reporting date.
Students confuse equity-settled with cash-settled awards, which are remeasured to fair value each period.
Fix: For equity-settled awards, fair value is locked at grant date. Only the forfeiture estimate changes expense later.
Saying higher volatility lowers the expense.
Volatility sounds like risk, so students link it to a lower value.
Fix: An option holder gains from upside and is protected on the downside, so volatility raises value and expense.
Ignoring forfeitures and using total options granted.
The vignette gives the grant size prominently and the forfeiture rate in a footnote.
Fix: Always multiply by (1 − forfeiture rate) before spreading over the vesting period.
Applying the treasury stock method to out-of-the-money options.
Students plug numbers into the formula without checking exercise price against average price.
Fix: If exercise price is at or above average price, the options are antidilutive and add no shares.
Treating share-based pay as free because it is non-cash.
The indirect-method cash flow statement adds it back to operating cash flow.
Fix: It is a cost borne by shareholders through dilution. Analysts often treat it as an expense when judging earnings quality.
Dividing the expense by the option's life instead of the vesting period.
Expected term and vesting period both appear in the data and are easy to mix up.
Fix: Expected term is a model input. Vesting period is the expense recognition period.

Worked examples

Example 1

A company grants 2,000,000 options on 1 January Year 1. They vest in full after 4 years of service (cliff vesting). Model-based fair value is $12 per option, and management expects 10% to be forfeited. (1) What is annual expense? (2) If expected volatility is raised so fair value becomes $14, what is the new annual expense? (3) At the end of Year 2 management revises expected forfeitures to 5%. What is Year 2 expense, given Year 1 expense was as in (1)?

Show the solution

(1) Options expected to vest = 2,000,000 × 0.90 = 1,800,000.
Annual expense = 1,800,000 × $12 ÷ 4 = $5,400,000.
(2) Annual expense = 1,800,000 × $14 ÷ 4 = $6,300,000. The change is $900,000 higher per year.
(3) Revised options expected to vest = 2,000,000 × 0.95 = 1,900,000.
Revised cumulative expense after 2 years = 1,900,000 × $12 × 2 ÷ 4 = $11,400,000.
Year 2 expense = $11,400,000 − $5,400,000 = $6,000,000.

Answer: (1) $5.4 million per year. (2) $6.3 million per year, so higher volatility raises expense. (3) Year 2 expense is $6.0 million, which includes the catch-up for the lower forfeiture estimate.

Example 2

Firm X has 100 million basic shares, net income of $250 million and an average share price of $40. It has 5,000,000 options outstanding with an exercise price of $30. Firm Y has similar business, option terms and share-price behavior to Firm X, but uses expected volatility of 25% while Firm X uses 40%. (1) How many incremental shares does Firm X add under the treasury stock method? (2) What is diluted EPS? (3) What does the volatility difference suggest?

Show the solution

(1) Options are in the money because $40 exceeds $30.
Incremental shares = 5,000,000 × (1 − 30 ÷ 40) = 5,000,000 × 0.25 = 1,250,000.
(2) Diluted shares = 100,000,000 + 1,250,000 = 101,250,000.
Diluted EPS = $250,000,000 ÷ 101,250,000 = $2.47 (basic EPS is $2.50).
(3) Lower volatility gives lower option fair value, and so lower expense and higher earnings, than if Firm Y used Firm X's input. This is not proof of understatement, because the firms may differ in ways the data do not show.

Answer: (1) 1,250,000 incremental shares. (2) Diluted EPS is about $2.47. (3) Firm Y's lower volatility suggests its compensation expense may be understated, but it is not proof. This warrants comparing the two firms on consistent assumptions before drawing a conclusion.

Exam tips

Know the direction of every input on option value cold. Many questions are only that.
Expect an exhibit table of assumptions for two firms. Pick the firm whose volatility, term or dividend yield lowers its expense relative to the peer.
Check whether the award is equity-settled or cash-settled before deciding on remeasurement.
In dilution questions, test in-the-money first, then use average market price, not the period-end price.
If asked for an analyst view, say what changes in expense, EPS and cash flow presentation, and that the cost is real even though it is non-cash.

Option Valuation Assumptions and Analytical Implications: frequently asked questions

Which Black-Scholes assumptions most affect stock option expense?

Expected volatility and expected term have the largest effects, and both are management estimates. Higher values raise fair value and expense. Dividend yield and risk-free rate matter too, but have less room for judgment.

Does a change in share price after grant change the expense?

For equity-settled awards, no. Fair value is set at the grant date and is not remeasured. Only changes in the expected number of options that will vest, such as forfeiture estimates, alter later expense.

How does share-based compensation affect the financial statements?

It increases compensation expense and lowers net income, with a matching increase in equity, so no cash leaves. It is added back in operating cash flow under the indirect method, and exercised options raise the share count and dilute EPS.

How should an analyst judge option valuation assumptions?

Compare volatility, expected term and dividend yield with peers and with the firm's own history. Unusually low volatility or short term lowers expense and flatters earnings. Also review the notes for options outstanding and unrecognized cost.