Yield to Market refers to the following calculation:
Yield to market is also called Current Yield.
So, for example, if you had a bond that payed $40 semiannually, and the current price of the bond was $940, the Yield to Market would be 8.51%.
Yield to Maturity is not a very good measure of a bond's value. It does not take into consideration the price paid for the bond, nor the prevailing interest rates, nor the credit rating of the bond.