What happened

Ford Motor Company (F 0.17%) stock enjoyed a modest tailwind Thursday, closing the day up 3.1% after announcing that its new electric F-150 Lightning pickup truck will go on sale next year for the low, low price of $39,974. That's just $74 more than Tesla (TSLA -3.55%) says it will sell its Cybertruck for, and with Ford beginning sales in 2022 -- but Tesla not saying when its Cybertruck will arrive -- Ford's F-150 Lightning might even beat Cybertruck to market. 

And yet, while it was Ford that made the headlines, it was Tesla stock that went up more today: 4.1%.

Tesla Cybertruck.

Tesla's Cybertruck. Image source: Tesla.

So what

So how did Tesla steal Ford's thunder? (I mean, its Lightning?)

I've got a couple of theories. The most likely is that investors are viewing Ford's electric F-150 bet as validating Tesla's idea of selling electric pickup trucks, and as a sort of backhanded endorsement that Tesla was right all along about the future of cars -- and trucks -- being electric.

A second factor possibly helping out Tesla investors is that famed tech investor Cathie Wood snapped up another 69,508 shares of Tesla today for three of her ARK investment funds. Combined with the more than 47,000 shares Wood purchased the day before, that makes for about 116,500 Tesla shares she's added to her holdings this week -- the first such buying she's engaged in since April.  

Now what

After a month of nearly continuous selling of Tesla stock on the market, driving shares of Elon Musk's car company down nearly 25%, investors may be taking Wood's buying as a "green light" signal that it's safe to get back in the water again.

And not even a press release from Ford could stop this rally.