Nvidia, Palantir, and Broadcom Are Sending Shockwaves Through Wall Street With This $4.6 Billion Warning

Nothing has captured the attention of investors since the advent and proliferation of the internet in the mid-1990s quite like the rise of artificial intelligence (AI). Empowering software and systems with the tools to make split-second, autonomous decisions is a multitrillion-dollar addressable market.

Arguably, no companies have benefited more from the evolution of AI than graphics processing unit (GPU) titan Nvidia (NASDAQ: NVDA), data-mining specialist Palantir Technologies (NASDAQ: PLTR), and networking solutions kingpin Broadcom (NASDAQ: AVGO). Broadcom joined the trillion-dollar club in December 2024, Nvidia became the first public company to top $5 trillion in October 2025, and Palantir shares have skyrocketed 2,100% since the end of 2022.

While all three companies possess undeniable competitive advantages, the people who know these businesses best are sending worrisome signals.

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Insiders are sending a message -- are you paying attention?

No group understands a company better than its insiders. An "insider" is a high-ranking executive, board member, or beneficial owner of at least 10% of a company's outstanding shares. These are individuals who may possess non-public information.

Insiders are required by law to file Form 4 with regulators anytime they purchase or sell shares of their company, including the exercising of option contracts. This filing has to be made within two business days of a transaction.

Based on aggregated Form 4 filings over the trailing year (as of April 28, 2026), insiders at these AI juggernauts have sent shockwaves through Wall Street with their heavy net-selling activity:

• Nvidia: $2,396,602,073 in net selling
• Palantir: $1,058,424,816 in net selling
• Broadcom: $1,144,516,490 in net selling

Collectively, the hardware, networking, and application companies leading the AI revolution have seen their insiders dispose of approximately $4.6 billion in shares over the trailing 12 months.

The caveat to this data is that not all insider sales are inherently nefarious. Since most high-ranking executives and board members receive the bulk of their compensation as stock or options, they often sell shares of their company's stock to cover their federal and/or state tax liability. There are several reasons to sell a stock, and tax-based selling isn't something investors should be worried about.

But the other side of this coin is just as important. Whereas several reasons exist to sell a stock, there's only one reason to be a buyer: the belief that shares will appreciate. Nvidia hasn't had a single insider purchase over the trailing year, while Palantir's and Broadcom's insiders have scooped up just $3.32 million and $1.55 million in shares, respectively.

Insiders aren't buying, which may signal that the people who know these companies best don't view their stock as a bargain.

The time-tested price-to-sales (P/S) ratio strongly suggests this AI trio is historically expensive. Over the last three decades, P/S ratios above 30 for companies at the forefront of next-big-thing trends have signaled the presence of a bubble. As of the closing bell on April 28, Nvidia, Broadcom, and Palantir had respective trailing 12-month P/S ratios of 24, 28, and 81.

Executives at Nvidia, Palantir, and Broadcom may be optimistic about their company's future, but their actions say otherwise.

Sean Williams has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends Broadcom, Nvidia, and Palantir Technologies. The Motley Fool has a disclosure policy.