If you've been following stock market news, you're no doubt aware that we've officially plunged into bear market territory due to fears of COVID-19. A bear market means stock values have plummeted at least 20% from a recent high, and are likely to stay down for a period of time. That's not good news for investors who need to tap their stock portfolios for cash in the coming weeks. But for some people, it actually presents a solid buying opportunity. After all, quality stocks that were once hard to acquire are suddenly cheaper -- a lot cheaper. As such, now's actually a great time to invest some of the cash you're not using.

But what if you don't have piles of cash in the bank? Should you tap your emergency fund to capitalize on the opportunity to make money in the long run? Or leave your savings alone?

The danger of raiding your emergency fund

Health officials are calling for a heavy dose of social distancing to curb the spread of COVID-19. That means countless Americans may have to take time off of work, whether because it's not safe to go in or because their children's schools are closed and they therefore have no child care.

Person at ATM holding hundred-dollar bills

IMAGE SOURCE: GETTY IMAGES.

The result? A large number of Americans are likely to take a hit on income in the coming weeks or months, which means now's definitely not the time to raid your emergency cash reserves if you're fortunate enough to have any.

And to be clear, many Americans don't have that safety net. An estimated 39% of U.S. adults don't have enough money in the bank to cover a mere $400 expense.

But if you do happen to have a solid emergency fund -- one with enough cash to cover three to six months of essential bills -- it's more important than ever to leave that money alone. Right now, life in the U.S. is far from normal, and it's too soon to know when things will begin to stabilize. But one thing's for sure: Having several months' worth of living expenses on hand could end up being a lifeline, so tempting as it may be to use some of that money to capitalize on a lucrative investing opportunity, you're better off playing it safe and leaving that cash where it is.

On the other hand, if you have extra cash lying around outside your emergency fund, now's a good time to spend it on stocks. But don't expect to cash out those investments quickly -- it may be a while before the stock market recovers from its recent crash, and if you're looking to get in and get out quickly, you may wind up disappointed.

One final thing: Maybe you're in the fortunate situation of not having your income interrupted while thousands of employers transition to work-from-home arrangements or make accommodations to pay workers who can't do their jobs remotely. That's a great spot to be in, but don't get cocky. We don't know what long-term impact COVID-19 will have on our economy, and whether it will spur a full-blown recession, but it's safe to say that it's already wreaking havoc. As such, you should make an effort over the next few weeks or months to not only leave your emergency fund intact, but bolster it. Chances are, some of the things you'd normally spend money on are off the table for the time being anyway, so take the opportunity to pad your savings -- because, unfortunately, we just don't know how bad things will get.