The market started 2026 on a positive note, with the S&P 500 climbing 1.3% in the first week of trading, buoyed by geopolitical developments including the U.S. government's removal of Venezuelan President Nicholas Maduro. But if you look beneath the surface, some warning signs are starting to flash for a handful of once-beloved growth stocks.

Here's the thing about expensive markets: they're great until they're not. And right now, some widely owned names are facing the triple threat of competitive headwinds, stretched valuations, and fundamental business risks that could overwhelm any near-term optimism. As usual, the priciest sectors are the ones most at risk.

Dan Buckley, chief analyst at DyTrading.com, points to 2022 as a cautionary tale. That year hammered home what happens to long-duration equities when interest rates rise more than expected. "Lots of institutional money pulls back when they have safer investment opportunities that provide a more acceptable baseline yield," he explained.

"Technology, most notably and probably most unsurprisingly, is in the crosshairs," Buckley said. "That's especially so with high-earnings-multiple tech stocks and for companies that struggle to earn with problematic business models. The distribution of outcomes is often much wider with those stocks because of their growth narratives and because they come with more volatility."

Translation: when the market gets nervous, the expensive stuff gets hit first and hardest. So let's look at three stocks that might deserve a spot on your sell list as fundamentals threaten to catch up with expectations.

Uber's Autonomous Vehicle Problem

One Month Performance: -4.65%

Uber Technologies (UBER) has a serious problem on its hands, and it's rolling toward them at high speed. The rise of autonomous vehicles could fundamentally reshape the ride-sharing industry, and Uber might find itself on the outside looking in.

Here's the awkward part: Uber exited the self-driving race years ago. Meanwhile, its competitors kept pushing forward, and now they're potentially positioned to dominate an industry valued at $273.75 billion in 2025 that's expected to expand to nearly $4,450.34 billion by 2034, representing a compound annual growth rate of 36.30%.

Tesla, Alphabet's Waymo, and Amazon-backed Zoox are all investing heavily in robo-taxis that could completely upend ride-sharing economics. If autonomous fleets become commercially viable and widespread, Uber risks being reduced to just a middleman without drivers, without vehicles, and without valuable proprietary autonomous vehicle technology. That's a precarious position when your long-term pricing power and profit margins are increasingly vulnerable to rising competition and ongoing regulatory scrutiny.

The market is already taking notice. UBER stock fell 3% earlier this week after Melius Research downgraded it to Sell from Hold, slashing its price target to $73 from $100, citing tougher autonomous vehicle competition as the primary concern. Expect that downward pressure to continue throughout 2026 as Uber loses ground to better-positioned competitors.

Rivian's Cash Burn Problem

One Month Price Performance: +10.59%

Market experts say investors should immediately reconsider their positions in Rivian (RIVN) and similar unprofitable electric vehicle manufacturers. Despite recent gains, the fundamental picture looks challenging.

"While the technology is impressive, the math doesn't work," said David Jaffee, a former investment banker and founder of BestStockStrategy.com, an options and investment risk management service platform. "Rivian is a 'capital incinerator.'"

The core issue is simple but devastating: Rivian loses money on every vehicle they sell. "To survive, they must constantly raise capital, which dilutes shareholders," Jaffee explained. "And in 2026, time is the enemy. Legacy automakers and the market leader (Tesla) have the scale to wage a price war that Rivian cannot afford."

Think about that for a moment. You're competing in an industry where the dominant player can afford to cut prices, and you're already losing money on every unit sold. That's not a sustainable business model, it's a countdown clock.

Consequently, if you're holding Rivian, you're holding a lottery ticket with decaying odds. "Sell it and redeploy that capital into a company with robust free cash flow, or use the capital to sell put options on profitable blue chips to generate immediate income," Jaffee advised.

Affirm and the Consumer Credit Crunch

One Month Price Performance: +10.59%

Jaffee is also bearish on fintech lenders and "Buy Now, Pay Later" companies, particularly Affirm (AFRM).

"The consumer balance sheet in 2026 is showing cracks," he noted. "We're seeing delinquency rates tick up in credit cards and auto loans. Sectors that rely on subprime or near-prime consumer credit (like Affirm or Upstart) are facing a dual threat: borrowing costs remain real, and default rates are rising. When the economy normalizes, these are the first stocks to suffer because they lack the 'moat' of the major banks."

That last point matters more than you might think. When times get tough in consumer lending, the companies with strong balance sheets, diversified revenue streams, and regulatory advantages weather the storm. BNPL companies that rely on a specific demographic and credit profile? Not so much.

Trimming Tech Exposure

Beyond individual stocks, Buckley suggested that investors with heavy technology exposure might want to rebalance, though not dramatically.

"If I had imbalanced exposure to the AI trade, I'd cut back in big names, notably Nvidia (NVDA) and Advanced Micro Devices (AMD)," he said. "I don't believe the producers of those technologies will be the biggest winners long-term, given the economics, exponential capex commitments, and starting valuations."

It's a fair point. Being the picks-and-shovels provider in a gold rush sounds great until you realize you need to spend billions on new factories while your customers are still figuring out how to monetize their own AI investments.

The Bottom Line

The broader market may still be leaning toward growth, but select stocks like Uber, Rivian, and Affirm are flashing warning signs as we move deeper into 2026. For investors focused on capital preservation and risk management, these three stocks may be better candidates for trimming or selling outright before downside risks become reality.

Sometimes the hardest part of investing isn't finding winners. It's knowing when to walk away from yesterday's favorites before they become tomorrow's regrets.