<prompt> Human: I have a balance on a 0 CC where the 0 rate expires in November. I was wondering if I could put my tax return into my Vanguard Roth IRA, invest it in BND, and then take it out before November and pay off the card? Or is that a bad idea? I was thinking that or something else that is low-risk...wondering if thatd be a good idea over my Ally Savings account. If I withdraw just before November, will I gain back the 5,500 contribution limit?  <response>: I was thinking that or something else that is low-risk...wondering if thatd be a good idea over my Ally Savings account.The price of BND is not a monotonically increasing function. Your Ally balance is.Over the past 5 years, BND has averaged about 2 growth. If we assume a 2000 tax return which is a bit high, thats 30 in growth with BND, on average. Ally would net you 15 in interest over that time.Essentially, youre asking whether or not it would be worth it to gamble your tax return over an expected value of 15 in additional gains, and this doesnt even take into account the tax implications of doing soEven though the expected value is higher, I see no compelling reason why you should put the money in your IRA just to withdraw it in November. 