Timeline for the homebuyer tax credit
By this date, the Federal Reserve plans to stop buying mortgage-backed securities. This matters because many economists and mortgage bankers expect mortgage rates to rise when the Fed withdraws from the market and investors step in. To be assured of getting the lowest mortgage rate, you need to have the rate locked by the end of March. And to have a locked rate, you need to have a house under contract. You can't lock a rate while you're still looking for a house.