If you think the slow U.S. economy is the biggest worry for U.S. tech companies right now, you're wrong. In fact, large U.S. technology companies are more concerned about other troubles -- like what's going on with their businesses outside the United States.

The 100 largest publicly traded U.S. technology companies are most nervous about industry consolidation and competition; uncertainty about U.S. and foreign government regulations, including taxes; and risks involving their international operations, according to a new report.

The report by professional services firm BDO Seidman lists the "top 20 risk factors of the 100 largest U.S. technology companies" based on risk information culled from those companies' fiscal 2007 Securities and Exchange 10-K filings. The general condition of the U.S. economy ranked seventh on the risk list.

"I would've thought the U.S. economy would be a bit higher on the list, but tech companies seem to be a bit insulated from the slow economy this time around, maybe because of their global expansion," said Doug Sirotta, a BDO Seidman Technology Practice partner, in an interview with InformationWeek.

And with that emphasis on global expansion, it's not so surprising that concerns and uncertainty related to international operations ranked higher -- and frequently -- in those companies ' risk factors, he says.

Based on BDO Seidman's analysis of the SEC filings, as U.S. tech companies are expanding globally -- including into developing markets -- the top risks they face include challenges in managing merger and acquisition transactions (86%), inability to market or develop new products and services for global regions (84%), and intellectual property infringements (84%).

Competition and consolidation in the tech industry was the number-one risk, faced by 92% of the companies, followed by changes to government regulations and taxes both inside and outside the U.S., which is a risk for 87% of companies.

For instance, "there is a lot of uncertainty right now about India, its regulations are very complex," Sirotta said. "India requires a lot of reports and disclosures," and some of those rules are continuing to evolve, he says.

Risks to international operations ranked third, with 86% of companies facing those challenges. However, several of the other top 20 risks were also related to global challenges, including U.S. and foreign supplier and vendor concerns, which ranked 13th on the list.

The risks were ranked by order of the frequency cited in the SEC filings.

Here's BDO Seidman's full list of "Top 20 Risk Factors of the 100 Largest U.S. Technology Companies." Percentages represent the portion of companies facing a particular risk based on their fiscal 2007 SEC 10-K filings.