YIELD is a financial function in Google Sheets that calculates the yield of a security with a fixed interest rate. It returns the annual yield of a security that pays periodic interest, such as a bond, based on its settlement date, maturity date, coupon rate, market price, redemption value, and payment frequency.

The syntax for the YIELD() function is as follows:

YIELD(settlement, maturity, rate, price, redemption, frequency, [daycountconvention])

settlement: the security's settlement date, which is the date the security is traded and the buyer pays for it. maturity: the security's maturity date, which is the date the security expires and the issuer pays the principal amount to the buyer. rate: the security's annual coupon rate. price: the security's market price per $100 face value. redemption: the security's redemption value per $100 face value. frequency: the number of coupon payments per year. Valid values are 1, 2, or 4. daycountconvention (optional): the day-count basis to use for the calculation. It is an optional argument, and the default value is 0, which means the actual number of days between settlement and maturity is used.

The YIELD() function is commonly used in financial analysis to determine the yield of a bond or other fixed-income security, given its market price and other relevant information.