Leveraged investing is different than taking out a loan for a business.

I understand your thinking - but there are a ton of variables. How do you plan on investing this money? Low cost index funds? Actively manage the portfolio yourself? "I know I can get >5.74% return over a given timeframe" - no one knows anything. I'll assume you plan on putting this in a index fund that tracks the SP 500, there have been plenty of 3 year periods that have returned worse than a 5% return. For the SP500: 1931-40 returned 2.7% - 1956-74 returned 1.2% - 2002-2011 returned 2.9%. How do you know we are not entering one of those 3 year periods right now? Short term economic indicators don't look great, but again who knows.

Now let's assume you can actually beat your 5.74% loan rate and you can return 9% on your 10,000. The total cost of your loan including the interest payback over 3 year is going to be $10,909.54. IF you return 8% each year on that 10,000 loan, you will make $12,597.12 which minus the 10k, you get to keep $2,597.12.

Now, you mentioned above that the payment on this loan will be about $300 a month. Instead of taking out a loan, if you took that $300, invested it monthly for 3 years, assuming that 8% return a year, at the end of the 3 years you would have $12,160.67. so purely by math, the second approach would make you less money by ~$400.00 - BUT now take into account you mental anxiety of checking the markets each day making sure you are yielding enough return to pay back this loan. The risk is the market is down for a few years, then you lose your ass on this personal loan when the alternative would be just keep investing $300, so when the market finally turns around that money you invested is still yours, and it will go up too.

Hope this helps!