DoD funding, page-5

United States law says that any intellectual property developed with Defense Department funding belongs to the government. And even when technology is developed with private funding the Defense Department, before committing to buy products using that technology, generally requires that the owner/seller give the government a perpetual royalty free license to use it and to provide it to competitors so they can bid competitively. That's why many U.S. firms that have cutting edge technology don't deal with the government. The issues are well summarized here.