Investors in Rivian Automotive (RIVN 3.04%) got a rare bit of good news on Tuesday. After falling for four straight days -- including a sharp drop yesterday on news the electric-car market has gotten so bad that Tesla (TSLA 14.22%) must lay off 10% of its workers -- shares of Rivian jumped 4.3% through noon ET today.

One bank says Rivian is no longer a sell

Up until yesterday, investment bank UBS had Rivian stock pegged for a sell rating and a $9 price target. Today, UBS still thinks it's worth only $9 a share, a far cry from the $130-plus the stock fetched back around its initial public offering. But the bank no longer thinks it's a sell.

Last night, UBS upgraded Rivian to neutral as the stock approaches its price target. "The stock price now better considers some of our midterm concerns," the bank said.

UBS now believes $9 is the right price if Rivian does only $4.5 billion in sales next year. If the electric-vehicle (EV) company can reach $5.1 billion in sales (as the bank predicts), the stock might actually go up. And any money from pre-orders for its upcoming R2 electric SUV might help to make that happen.

Of perhaps greater concern to investors, UBS said that short interest in Rivian stock has grown to 18.7%, which makes it increasingly risky to short it (or even keep a sell rating on). Should the EV maker post good news in its next earnings report, or even just promise good news in its guidance, traders might decide to begin covering their shorts, buying back Rivian shares and forcing the price even higher.

In short, what UBS really seems to be worrying about here is a short squeeze. Long term, it's still probably not a great idea to invest in a money-losing EV company like Rivian. But in the short term, it could be an even worse idea to short it.