They're the same company: Silencerco bought SWR a few years ago and merged employees and manufacturing, but for a while they kept them as separate entities with separate websites and separate product lines, using SWR for their more conventional designs and Silencerco for their more innovative designs. For example, when I bought my Octane 9 it was still considered an SWR silencer; it says SWR on the box and it has SWR in big letters on the tube. But it also says Silencerco in smaller letter on the tube. And the Form 3 was from Silencerco, so that's what it says on my Form 4.
As recently as last year, Silencerco reps were saying they were still still planning to keep the companies as two separate design philosophies (even though the employees and manufacturing had been completely merged for a while), but sometime towards the end of last year I noticed that they merged their websites and they seem to have gotten rid of the SWR name altogether. I wonder if silencers that used to be sold under the SWR name are still being made with SWR on the tube? But it doesn't really matter; it's still the same silencer no matter what company name they put on the tube.
I worked at an 07/02 FFL/SOT for two years, and I was able to really examine which pistol silencer I wanted to buy. And I decided on the Octane 9; I think it's the best pistol silencer on the market, hands down.