Is Rivian stock a short-squeeze candidate? UBS seems to think it is.Investors in Rivian Automotive (RIVN 3.82%) 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 -2.89%) 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 sellUp until yesterday, investment bank UBS had Rivian stock pegged for a sell rating and ...