<prompt> Human: hey rpersonalfinance I just filed my taxes today and I received a tax refund and was wondering how much money that could have been if I investing it in monthly installments into an SP 500 index fund. Receiving a tax refund is in essence giving the government a interest free loan.Here are the results of adjusting your withholds to receive a 0 refund while investing the difference into VFINX Vanguards SP 500 Index Fund I will note that this does not include dividend payments but I will include that information below 3212014 172.04 Per Share 0.73 Dividend 6202014 181.01 Per Share 0.76 Dividend 9192014 185.43 Per Share 0.83 Dividend 12172014 182.79 Per Share 0.98 DividendIf anyone wants to play around with the spreadsheet:Assistant: Id rather have a refund. I know Im not running at 100 efficiency, but the extra dollars I would get each week would end up being spent on dumb stuff, whereas this year Im applying 100 of my refund to an IRAHuman: can you lone me 5,500 interest free and in one year I will promise to pay you back before the IRA contribution cut off date.  <response>: the interest free loan dogma overblown. the guy says he would spend the money and not invest in anything if it were in his regular paycheck. Because he receives it all in one lump sum he invests it in an IRA. there is no one-size-fits-all strategy to this. as long as he is savinginvesting using this method that is fine. Do you know what will happen in tomorrows markets? He may actually come out on top if the market drops during the year and he invests his lump sum at the bottom of a bear market the following year. FYI, I personally prefer to get no refund either. 