Ridgid. A few years back I saw one in a store that said Craftman on the handle but Ridgid on the jaws. It could have changed in the last few years but if it is still USA I doubt there has been a change in OEM.
The ones at work that are branded "craftsman" also have "WF" cast in the handle just above the hole in the handle. Its funny the brand new Snap on pipe wrenches that we just got also have "WF" in the same spot. Hmmm......
Reed used to make most of Craftsman plumbing tools, not sure if they still do, I would guess the new stuff is made by a company with a name like Shanghai Chicago Pipers Tools.