Is It Time to Buy October's Worst-Performing Nasdaq Stocks?

October 2024 was a fairly quiet month on Wall Street. The major market indices stayed within 3% of their starting scores throughout the month despite economic uncertainty and a nerve-wracking election cycle.

But the stock market never sleeps, especially in its more growth-oriented and volatile sectors. Four of the 101 stocks in the NASDAQ-100 index gained more than 10% last month, while 12 stocks posted double-digit price drops.

Some of those sharp price drops might open buying windows. Others could be big, red flags highlighting companies in deep trouble. So let's take a look at some of the worst-performing Nasdaq-100 stocks in October. Are there any promising investment ideas in this group?

Data collected from Google Finance and Finviz on 11/5/2024.

Sliding healthcare stocks

First, I'll admit that medical research isn't my forte. Therefore, I'll keep the analysis brief for the healthcare companies on this list.

Regeneron

Regeneron's plunge followed after the release of third-quarter results, which beat analyst estimates but still inspired a dramatic price correction. The company has a deep pipeline of drug candidates, but the important Eylea vision-impairment treatment is losing ground to newer alternatives and biosimilar drugs.

Before the report, fellow Fool Adria Cimino saw Regeneron as a likely stock-split candidate. Now, it seems to be a value-priced medical titan. Make sure to double-check my view with real experts in the field, but the stock looks worthy of a deeper dive today.

Idexx

Idexx also reported results in October and was met with the same market skepticism as Regeneron. This was more of a mixed report, though -- Idexx met Wall Street's consensus bottom-line estimates but fell short on revenues. The stock entered 2024 on a high note but has now given back the gains it saw in the fall of 2023.

The company faced lower revenue and weaker profit margins in the livestock department, but the much larger category of pet products saw 6.5% year-over-year sales growth and significantly wider operating margins. Idexx shares aren't cheap even after October's sudden price drop, and the lagging livestock business is concerning. Once again, this industry is not in my wheelhouse, but the mixed financial results and lofty valuation ratios don't add up to a great buying idea.

Moderna

Finally, advanced-vaccine expert Moderna didn't report earnings in October. Instead, the stock continued a long and painful slide.

The COVID-19-vaccination boom is over, and Moderna sees slow uptake of seasonal vaccines this fall. The company faces several patent-infringement lawsuits, threatening to undermine what's left of the COVID-19 prevention market. The company is currently unprofitable, and its pipeline of potential blockbusters looks slim.

As with Idexx and Regeneron, you should find Moderna experts with a deeper knowledge of this market. From my view as a casual observer, I'm not inspired to pick up Moderna shares today. The risks of holding this stock seem greater than the rewards.

Struggling technology experts

That leaves me with two companies I do understand. Unfortunately, they generally don't strike me as great stocks to buy right now.

Supermicro

Server-systems builder Supermicro is reeling from a potential accounting scandal. A short-seller analyst firm started the ruckus with an ultrabearish report; Supermicro's annual report for fiscal year 2024 is overdue; the Justice Department is investigating its financial filings; and giant auditor firm Ernst & Young has resigned from Supermicro's service. The company reported results on Nov. 5, but investors and regulators alike may doubt the accuracy of the reported numbers.

After skyrocketing as a key system builder for artificial intelligence (AI) clients, Supermicro is losing market reach and customer confidence. The company should be considered innocent until proven guilty of poor accounting, but perception quickly becomes the reality. Whatever follows from the legal review and auditor shakeup, it will take years to rebuild this damaged brand in the best-case scenario. Meanwhile, arch rival Dell (NYSE: DELL) offers a similar hardware-based on-ramp to the AI opportunity without the financial-reporting drama. Dell stock isn't even expensive, trading at a modest 24 times trailing earnings.

ASML

Finally, semiconductor manufacturing is a hot topic, but you wouldn't guess it by looking at key equipment provider ASML. The company reported Q3 results in the middle of October with soft order bookings and a disappointing market outlook.

ASML's largest customers are dragging their feet on infrastructure upgrades. "The recovery is more gradual than previously expected," CEO Christophe Foquet said in the earnings release.

Investors had expected a triumphant sales surge as semiconductor makers geared up to support the AI boom. Instead, they're watching chip foundries pinching pennies until consumers and businesses ramp up their actual demand for AI-powered services.

ASML's disappointing report may be a red flag for AI investors in general. I'll wait for a steeper price reduction before starting a position in ASML Maybe it's best to focus my AI interest on user-facing services these days.

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Anders Bylund has no position in any of the stocks mentioned. The Motley Fool has positions in and recommends ASML. The Motley Fool recommends Idexx Laboratories and Moderna. The Motley Fool has a disclosure policy.