Palantir and BigBear.ai have gone in opposite directions since their market debuts. Palantir, which opened at $10 on its first day, now trades at nearly $120. BigBear.ai, which opened at $9.84 after its SPAC merger, now trades at about $9. Let's see why the bigger AI company outperformed the underdog, and if it's still the better investment now.

If you have been following the artificial intelligence (AI) revolution over the past two years, chances are you're familiar with a software company called Palantir Technologies (NASDAQ: PLTR). Since last January,

Palantir (PLTR) stock is tumbling 11% after its CEO implemented a new stock-trading plan and a report stated that the Pentagon would look to cut its spending significantly. Meanwhile, investment bank Wedbush defended PLTR stock.

Palantir's valuation is retreating today after Walmart issued sales guidance for this year that spooked Wall Street. On the heels of a 5.6% increase for its annual revenue last year, the retail giant only expects sales growth to be between 3% and 4% this year.

Related: Walmart, Booking.com will rock markets in a busy earnings week But there was probably more behind the selling, including that Palantir's shares had become way too pricey and were vulnerable to a selloff.