A term used in derivatives trading, such as with options. A derivative is a financial instrument whose price is based (derived) from a different asset. The underlying asset is the financial instrument (e.g., stock, futures, commodity, currency, index) on which a derivative's price is based.

For example, an option on a stock gives the holder the right to buy or sell the stock for a specified amount (strike price) at a certain date in the future (expiration). The underlying asset for the stock option contract is the company's stock.