Rivian Has Doubled. It’s Time to Pump the Brakes—a Little.

Rivian stock has more than doubled in the past week, since the electric truck maker’s smash initial public offering. Now is a good time for investors to put on their seatbelts—because the road is undoubtedly going to get bumpy.

No, this isn’t a call to abandon Rivian Automotive (ticker: RIVN) for those who believe Rivian is the next Tesla (TSLA)—an idea Barron’s heard from a barber. And no, Barron’s isn’t a Rivian bear. We even pointed out a couple of weeks back that a $64 billion valuation for Rivian actually made some…