At the very least, during periods when interest rates are significantly above your mortgage rate, such as now, you should put it in a money market account inste

At the very least, during periods when interest rates are significantly above your mortgage rate, such as now, you should put it in a money market account instead of in your mortgage. It's the same amount of risk, but it's liquid. Really, you could do a long term Treasury bond for the same reasoning (same risk, same liquidity).