It's still being made for audio use by Neotech / Harmonic Tech.
I buy some custom OCC wire for my cables from them, and I also carry some Harmonic Speaker cable, as imo it's the best UPOCC copper speaker cable value for the money.
Furukowa of Japan has stopped producing OCC wire and has moved onto Triple-C copper. Apparently is is made in a process similar to forging and has long aligned grain boundaries. However, even years later some Furutech cables still have some OCC copper in them, I heard they stockpiled some of it. Their latest PC, the DPS-4, uses both OCC and Triple-C copper.