Raytheon, one of the U.S. government’s largest military contractors, and United Technologies Corp. (UTC), an aerospace design and manufacturing company that also has strong military ties, are combining in an all-stock merger that promises to create a leviathan of military technology and equipment valued at $100 billion.

President Donald Trump sounded a skeptical note about the deal on CNBC on Monday, saying he was “a little concerned” that it could harm competition. Raytheon CEO Tom Kennedy countered that the companies are “complementary, not competitive.” (Kennedy will serve as executive chairman of the merged company, with current UTC leader Greg Hayes at the helm as CEO.)