An employee stock option gives you the right to buy ("exercise") a certain number of shares of your employer's stock at a stated price (the "award," "strike," or "exercise" price) over a certain period of time (the "exercise" period).

Incentive stock options (ISOs) in which the employee is able to defer taxation until the shares bought with the option are sold. The company does not receive a tax deduction for this type of option.

Nonqualified stock options (NSOs) in which the employee must pay income tax on the 'spread' between the value of the stock and the amount paid for the option. The company may receive a tax deduction on the 'spread'.

Employee stock options come in two basic flavors: nonqualified stock options and qualified, or "incentive," stock options (ISOs). ISOs qualify for special tax treatment. For example, gains may be taxed at capital gains rates instead of higher, ordinary income rates. Incentive options go primarily to upper management, and employees usually get the nonqualified variety.

How do Stock options work? An option is created that specifies that the owner of the option may 'exercise' the 'right' to purchase a company's stock at a certain price (the 'grant' price) by a certain (expiration) date in the future. Usually the price of the option (the 'grant' price) is set to the market price of the stock at the time the option was sold. If the underlying stock increases in value, the option becomes more valuable. If the underlying stock decreases below the 'grant' price or stays the same in value as the 'grant' price, then the option becomes worthless.

They provide employees the right, but not the obligation, to purchase shares of their employer's stock at a certain price for a certain period of time. Options are usually granted at the current market price of the stock and last for up to 10 years. To encourage employees to stick around and help the company grow, options typically carry a four to five year vesting period, but each company sets its own parameters.

There are three main ways to exercise options:

You can pay cash, swap employer stock you already own or borrow money from a stockbroker while simultaneously selling enough shares to cover your costs.

It's usually smart to hold options as long as you can.

Conventional wisdom holds that you should sit on your options until they are about to expire to allow the stock to appreciate and, therefore, maximize your gain. In the aftermath of the tech stock swoon, that logic may need some revision. In any event, you should not exercise options unless you have something better to do with the realized gain.

There may be compelling reasons to exercise early.

Among them: You have lost faith in your employer's prospects; you are overweighted on company stock and want to diversify for safety; you want to lock in a low-cost basis for nonqualified options; you want to avoid catapulting into a higher tax bracket by waiting.

Tax consequences can be tricky.

Unlike the case with nonqualified options, an ISO spread at exercise is considered a preference item for purposes of calculating the dreaded alternative minimum tax (AMT), increasing taxable income for AMT purposes.

How do Stock options work? An option is created that specifies that the owner of the option may 'exercise' the 'right' to purchase a company's stock at a certain price (the 'grant' price) by a certain (expiration) date in the future. Usually the price of the option (the 'grant' price) is set to the market price of the stock at the time the option was sold. If the underlying stock increases in value, the option becomes more valuable. If the underlying stock decreases below the 'grant' price or stays the same in value as the 'grant' price, then the option becomes worthless.

They provide employees the right, but not the obligation, to purchase shares of their employer's stock at a certain price for a certain period of time. Options are usually granted at the current market price of the stock and last for up to 10 years. To encourage employees to stick around and help the company grow, options typically carry a four to five year vesting period, but each company sets its own parameters.

Nonqualified Stock Options
Grants the option to buy stock at a fixed price for a fixed exercise period; gains from grant to exercise taxed at income-tax rates

Restricted Stock
Outright grant of shares to executives with restrictions to sale, transfer, or pledging; shares forfeited if executive terminates employment; value of shares as restrictions lapse taxed as ordinary income

Performance shares/units
Grants contingent shares of stock or a fixed cash value at beginning of performance period; executive earns a portion of grant as performance goals are hit