Yes, Microsoft now holds the patents for HDCD from when they bought Pacific Microsonics. Microsoft is trying to integrate it into online media.
If Sony/Philips had also owned HDCD, it would probably be part of every DAC chip made today, and would have been the standard long long ago. HDCD does not have the compatibility problems with Redbook like SACD does. HDCD is more like an enhancement or upgrade to Redbook, rather than a totally different technology like SACD. But SACD is the one being pushed hard because Sony/Philips does also own that (which is not catching on because of the added cost).
If Sony/Philips had also owned HDCD, it would probably be part of every DAC chip made today, and would have been the standard long long ago. HDCD does not have the compatibility problems with Redbook like SACD does. HDCD is more like an enhancement or upgrade to Redbook, rather than a totally different technology like SACD. But SACD is the one being pushed hard because Sony/Philips does also own that (which is not catching on because of the added cost).