Photograph by David Paul Morris/Bloomberg
5. Apple (Tied)
Twenty-four percent of the top 50 U.S. technology companies singled out the iPhone maker as a threat in their annual filings with the SEC. Intel and Microsoft were among the 12 companies that listed Apple in the risk factors or competitors section of their 10-K reports.
Apple's gravitational pull can even make the company's partners uneasy, as was the case for Intel, which supplies the processors used in Mac computers. If the Cupertino, California-based tech giant decides to go to a rival chipmaker, watch out. And even though Apple has far surpassed Microsoft since the days of the Mac vs. PC war, the classic rivalry lives on in the mobile era.