Www
Image: Bfishadow, Flickr.

The Nasdaq 100 Index did much better than the Dow and S&P 500, picking up gains of 8% in what was generally a flat year for the broader benchmarks. Yet even though many of the tech stocks that make up the biggest stocks on the Nasdaq stock exchange exploded higher, some sectors of the index held its performance back. Let's look at the 10 worst performers in the Nasdaq 100 in 2015 to see what they say about the weakest areas of the stock market right now.

Stock

2015 Return

Micron Technology

(59.6%)

Western Digital (NASDAQ:WDC)

(44.3%)

Viacom (NASDAQ:VIAB)

(43.7%)

Seagate Technology (NASDAQ:STX)

(42.4%)

Bed Bath & Beyond

(36.7%)

NetApp

(34.7%)

Yahoo!

(34.2%)

Whole Foods Market

(32.7%)

Qualcomm

(30.6%)

21st Century Fox (NASDAQ:FOX)

(28.6%)

Source: S&P Capital IQ.

Perhaps the most interesting thing about this list is that there aren't any energy companies on it. That's a reflection on the composition of the Nasdaq 100, as large players in the oil and gas industry have consistently chosen to list of the NYSE instead.

Hard-driving declines
Still, you can see some broad themes play out on the list. First, the presence of hard-disk drive giants Western Digital and Seagate Technology point to the difficulties that the storage industry has had over the past year. Despite getting some respite from a brief uptick in PC demand in 2014, both companies have seen demand shift away from traditional hard-disk drive storage toward solid-state solutions.

Western Digital has attempted to bolster its position in that space by buying flash-expert SanDisk, but intense competition among flash-drive players has also put a crimp in profits there. Seagate, meanwhile, has focused on returning capital to shareholders through a strong dividend as a massive repurchase program. Neither strategy has inspired confidence in their stocks, but Seagate and Western Digital trade at attractive valuations as long as you think their businesses won't fall apart entirely.

Eventually, both companies will likely come up with more modern storage technology solutions for its clients. But 2015's performance shows that Western Digital and Seagate Technology have further to go before they get there.

Media fallout
The other major theme among losing stocks in the Nasdaq was the difficulty in the media industry. Both Viacom and 21st Century Fox have extensive exposure to the cable television industry, and cord-cutting among cable subscribers has led to a decline in viewership for their respective networks. Competition from streaming-video companies producing their own content has also presented increasing challenges for the media companies, and Fox has had to deal with increased prices for showing valuable sports content that have posed long-term threats to profitability if viewership trends don't reverse course and support rising payments to major professional sports organizations.

Fox can point to potential success on the film side of its business as a hedge against the cable industry's woes, but Viacom is arguably more dependent on traditional cable programming. Major cable networks hope that they can find ways to circumvent cable companies entirely, going direct to viewers by offering access to programming through home broadband and mobile devices. Yet unless they can find a way to sustain advertising rates in a shift toward mobile -- something that tech companies have struggled with -- then Fox and Viacom could see further pressure in the years to come.

Even though the Nasdaq 100 outperformed most market indexes last year, there were pockets of weakness that demand attention. By looking at prevailing trends, you can work toward outperforming the indexes by avoiding tough sectors like these and focusing instead on the companies with the best future prospects.

John Mackey, co-CEO of Whole Foods Market, is a member of The Motley Fool's board of directors. Dan Caplinger owns shares of Whole Foods Market. The Motley Fool owns shares of and recommends Qualcomm and Whole Foods Market. The Motley Fool owns shares of Western Digital.. The Motley Fool recommends Bed Bath & Beyond and Yahoo. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.