Companies borrow money to rebuy shares when their earnings are greater than the interest cost. If your earnings are rock solid, then you earn a return by rebuy

Companies borrow money to rebuy shares when their earnings are greater than the interest cost. If your earnings are rock solid, then you earn a return by rebuying your shares. Of course nothing is guaranteed so you need some margin of error. Interest < Earnings * risk Not surprisingly, when interest rates are low, companies borrow more money to do this. It's also a feedback cycle where companies pay higher prices to buy their own shares. But it's still worthwhile because money is cheap. Thus, answering the original question, a market crash won't likely happen until interest rates rise. Recently there have been data that suggests the Fed might be able to raise rates, thus the mini sell off. But there is nothing solid yet. It's not the big scare, but the environment is building that there could be one. Doesn't mean it'll happen though.