<prompt> Human: Hello rpersonalfinance,Im hoping someone can tell me if this is a good or bad idea. I have a 30-year fixed mortgage at 3.5. With bonds just hoovering around 3, why should I buy bonds at the moment? Isnt it a better idea to just put the money I planned to use to diversify my portfolio with bonds and just pay it into my mortgage instead? By paying to the mortgage I am guaranteed an immediate gain of 3.5.Thank you!  <response>: Isnt it a better idea to just put the money I planned to use to diversify my portfolio with bonds and just pay it into my mortgage instead?Yes, although keep in mind your mortgage isnt liquid like a bond fund. You cant easily take out your excess mortgage payments if you need to spend them. You would need to refinance the loan. 