Meta Platforms Inc. (META) shares took investors on a ride Thursday, popping early alongside Nvidia Corp. (NVDA) after the chipmaker's impressive earnings report, only to reverse course as Nvidia shares pulled back from session highs. The stock ended up trading slightly lower by afternoon.

The AI Validation Trade

Meta deserves some credit for Nvidia's standout performance. The social media giant helped power Nvidia's networking revenue surge to $8.2 billion in the third quarter, representing a massive 162% jump from the prior year.

Nvidia crushed expectations across the board: earnings per share of $1.30 beat the $1.25 forecast, third-quarter revenue of $57.01 billion topped the $54.88 billion consensus, and fourth-quarter guidance of $65 billion sailed past Street estimates of $62.4 billion. That guidance especially mattered, easing fears about a potential AI bubble.

For Meta, this initially looked like validation. The company has been spending aggressively on AI infrastructure, and Nvidia's blowout results suggested that spending spree makes sense. But when Nvidia shares retreated from their highs, Meta followed the leader downward.

Meanwhile, in Madrid

Adding to Thursday's drama, a Spanish court ordered Meta to pay 479 million euros (about $552.48 million) to 87 Spanish news outlets. The court said Meta used Facebook and Instagram ads to gain an unfair competitive advantage while breaking European General Data Protection Regulation rules.

According to the ruling, Meta illegally processed user data for five years and earned more than 5.281 billion euros in Spain from online advertising during that period. The judge determined competitors in the Spanish advertising market should split this money based on their market share.

The decision isn't final yet and can be appealed to the Provincial Court. If it stands, it could set a precedent for similar cases throughout the European Union.

Meta shares were down 0.54% at $587.18 Thursday afternoon.