Tesla is now the most valuable car company in America

Tesla on Tuesday became the largest automaker in the US by market capitalization.

The electric-car maker surpassed General Motors and Ford as its shares rallied above $300 for the first time, giving it a market cap of about $53 billion.

GM was worth nearly $50 billion. Its shares fell 3% on Monday, its biggest drop in nine months, after the company reported March sales that were weaker than analysts expected. Ford also fell.

However, Tesla jumped 7% on Monday after reporting record deliveries in the first quarter, up 69% year-over-year to a record 25,000 vehicles. The rally had put the company in second place ahead of Ford.

But Tesla still has some catching up to do globally; Japan-based Toyota is worth $177 billion, or more than three Teslas.

While Tesla's stock rose to new highs, traders increased their bets that the shares would fall. Those wagers have not yet paid off, as short sellers have this year lost nearly $3 billion, according to the financial-analytics firm S3 Partners.