Yield to maturity (YTM) is a financial term used to measure the total return an investor can expect to receive if they hold a fixed-income investment until its maturity date. It represents the annualized rate of return earned by an investor on their investment, taking into account the initial purchase price, the interest payments received over the investment period, and the final principal repayment at maturity.

YTM considers the present value of all cash flows associated with the investment, including coupon payments and the final principal payment. It takes into account the time value of money, meaning it factors in the timing and magnitude of each cash flow. YTM is expressed as an annual percentage rate (APR).

Investors use YTM as a benchmark to evaluate and compare different fixed-income investments. A higher YTM indicates a higher potential return but also implies a higher level of risk. YTM assumes that all cash flows will be reinvested at the same yield rate until maturity, which may not be a realistic assumption in practice.

It's important to note that YTM assumes the investor will hold the investment until maturity and that the issuer will fulfill all contractual obligations. Changes in market conditions, interest rates, or creditworthiness of the issuer can affect the actual yield realized by an investor if they decide to sell the investment before maturity.