Tesla, he says, is a no-touch here — either to back or bet against. At its peak on Tuesday, shares were up 48% for the week. It now looks to close out the week up 16%.
"It's one of the most dangerous stocks in the world. I don't want to own it; I don't want to short it. It's very speculative. Large-cap companies aren't supposed to trade like penny stocks — go up 20% one day, down 20% the next," said Tepper on CNBC's "Trading Nation" on Thursday.
This week's surge was partially due to a short squeeze — a large number of short investors who were forced to cover their open positions against the name by buying the stock when it began to take off. The stock then gave back some of those gains on concerns the coronavirus outbreak could hurt production and deliveries in China.
Matt Maley, chief market strategist at Miller Tabak, agrees that it could take a breather after such a steep runup.
"I sent out a note earlier this week when the stock was above $900 saying the thing had gotten ridiculously overbought and should pull back significantly, and I'm not ... a perma-bear on the stock by any means," Maley said during the same segment. "When we see these individual investors come in and buy the stock like that, that is usually a sign that a top is it."
Tesla's RSI, or relative strength index, traded as high as 94 earlier this week. Any reading above 70 typically signifies overbought conditions.
"It is extremely overvalued right now. From my perspective, the most optimistic expectations are built in, so now there is execution risk," added Tepper.
However, he notes that the unpredictability makes guessing its next move impossible.
"To be honest, I have no idea where this stock is going to trade tomorrow, because it has a mind of its own," said Tepper. But "the stock works when Tesla is in that planning and storytelling stage, but it doesn't work in the execution stage. Right now, we are entering that execution stage, so for us it's a no-touch."