What happened

Industrial bellwether stock General Electric (NYSE:GE), maker of aircraft engines, gas turbines, and medical equipment, joined with new manufacturing economy 3D printing stocks Stratasys (NASDAQ:SSYS) and 3D Systems (NYSE:DDD) in a broad stock market rally Tuesday -- a snapback in response to some of the worst days on the stock market that we've ever seen.

As of 1:40 p.m. EDT, shares of Stratasys had gained 12.3% over Monday's closing prices, 3D Systems was up nearly 9%, and GE had racked up a solid 5% gain.

Three colorful arrows racing straight up on a black background

Image source: Getty Images.

So what

None of the three companies has put out any news of note today to explain the sudden turnaround in their fortunes -- not even giant GE, which is so big you might think it would be putting out press releases of some sort on a daily basis.

Instead, all three stocks seem to be simply getting swept up in today's broad-based rally. Whether the rally continues may depend largely on why it formed in the first place.

Is this, for example, simply a matter of short-sellers closing bearish bets and collecting profits before resuming their selling once more? In that case, today's stock market rally could be followed by a string of new stock market crashes in coming days.

Or are investors warming up to promises of economic stimulus packages heard out of Washington -- bailouts for airlines and airplane makers that might benefit companies like GE (which sells airplane engines), as well as Stratasys and 3D (whose 3D printers can manufacture prototype and replacement parts useful in a variety of industries)? If investors become convinced that despite the coronavirus outbreak, the U.S. will somehow manage to buy its way out of the looming recession by printing government money, then there's at least a faint hope that in the coming days, investors might finally begin to make good some of the savage losses they've incurred over the last few weeks.

At least, a Fool can hope.