For years, the Nasdaq Composite (^IXIC 0.33%) has been an extraordinary performer. Even though it fell more than its peers in the bear market of 2022, it has also rebounded sharply so far in 2023. As the rally appeared to hit a wall, the Nasdaq reversed course on Wednesday, and it was down more than 1% in the early afternoon.

Tesla (TSLA -8.78%) was a big drag on the Nasdaq, as a downgrade from a Wall Street analyst sent shares of the electric car stock falling. Yet Peloton Interactive (PTON 3.59%) suffered an even more significant decline after professional stock traders weighed in on the interactive fitness specialist as well.

Tesla: Too far, too fast?

Shares of Tesla were down more than 5% early Wednesday afternoon. After a rally that has seen the electric vehicle pioneer's stock soar by 150% since late December, Tesla now has some investors wondering if the rebound has run its course.

Analysts at Barclays cut their rating on Tesla from overweight to equal weight. They also reduced their price target on the stock by $40 per share, setting a new target of $220.

Most of Barclays' concerns seemed to be short-term in nature. The analysts pointed to the sharp increase in the share price in recent months while noting that there still remain some unanswered questions about Tesla's core business. In particular, as Tesla aims to make pricing adjustments to account for changes in consumer demand, shareholders will need to watch closely for signs of excessive margin deterioration. Given how important Tesla's dominant profitability has been lately, it could be a negative for the stock if investors perceive that the automaker is sacrificing a key competitive advantage rather than making a smart move to boost market share.

Even Barclays believes that Tesla has plenty of long-term promise, both in electric vehicles and with its ancillary businesses. Yet with so much hype over deals involving its Supercharger network, Tesla will have to prove that it will remain financially strong even in the face of changing industry conditions and potential macroeconomic weakness.

Peloton can't gain speed

Elsewhere, shares of Peloton Interactive lost another 9% on Wednesday afternoon. The interactive fitness equipment specialist hasn't been able to build any positive momentum, and professional investors are starting to lose hope about its prospects for a full rebound.

Analysts at Wolfe Research downgraded Peloton stock from market perform to underperform, cutting its price target to a new level of $6 per share. The main problem with Peloton in Wolfe's eyes is that the company hasn't yet identified a way to get back on a sustainable growth trajectory.

Numerous problems with fitness equipment have damaged Peloton's reputation among consumers, and that was largely responsible for derailing the company's aspirations to turn those customers into lifelong subscribers to its digital content. Peloton has tried to pivot to allow third-party retailers to sell its equipment and to make bikes and treadmills available for rent, but there haven't been many signs that the company will be able to become profitable in the near future.

Peloton shares have fallen so far that even the hint of success could prompt a substantial bounce. Nevertheless, for those who want to see evidence that Peloton's fundamental business story is an attractive one, patience is starting to wear thin.