Rivian Stock Is Dropping Like a Stone. Blame Amazon.

Stock in Rivian Automotive is falling fast because it seems the start-up has competition in supplying electric trucks to Amazon.com, one of its investors.

Rivian (ticker: RIVN) stock was down 6% at $95.28 in late morning, while the S&P 500 had slipped 0.1%. The Dow Jones Industrial Average was up 0.3%.

Wednesday, Stellantis (ticker: STLA)…