Offer your insights or judgment on the input financial query or topic using your financial expertise. Reply as normal question answering

what are the downsides of rolling credit card debt in this fashion
Awesome, you are a math guy.  Very good for you.  In theory, what you are proposing, should work out great as the math works out great.  However have you taken a economics or finance coursework?  The math that they do in these class will leave a most math guys uncomfortable with the imprecision even when one is comfortable with chaos theory. Personal finance is worse.  If it were about math things like reverse mortgages, payday lenders, and advances on one income tax returns would not exist.   The risk derived from the situation you describe is one born out of behavior.  Sometimes it is beyond control of the person attempting your scheme.  Suppose one of these happen: In my opinion the market is risky enough without borrowing money in order to invest.  Its one thing to not pay extra principle to a mortgage in order to put that money in play in the market, it is another thing to do what you are suggesting.  While their may be late fees associated with a mortgage payment, a fixed rate mortgage will not change if you late on payment(s). On these balance transfer CC schemes they will jack your rate up for any excuse possible.  I read an article that the most common way to end up with a 23%+ credit card was to start out with a 0% balance transfer.  One thing that is often overlooked is that the transfer fee paid jacks up the stated rate of the card.   In the end, get out of consumer debt, have an emergency fund, then start investing.  Building a firm financial foundation is the best way to go about it.  Without one it will be difficult to make headway.  With one your net worth will increase faster then you imagined possible.