Gain on the sale of Section 1202 stock, which is qualified small business stock, is not fully taxable. This is because there’s an exclusion of gain for stock held more than five years. Assuming you satisfy this holding period test, the excludable percentage depends on when you acquired the shares:
An amount of gain on the sale of certain depreciable property that is treated as ordinary income in the case of personal property. Recapture is computed on Form 4797.