How do I tell if my options are ISOs or NSOs? It doesn't say on my options agreement.

[DDollar]

If you have Non Qualified Stock Options, and you exercised and held the stock, then the bargain element (the difference between the strike price and the Fair Market Value) would have been added to your income.  Shares of stock would have been sold to pay payroll tax, and the amount of the bargain element would have been included in Box 1 of your W-2.  If you exercised and held Incentive Stock Options, it would not have been a taxable event.  You should contact someone at your company to be sure!