"Microsoft divested itself of its stakes in the MSNBC channel in 2005 and in msnbc.com in July 2012."
I thought their Edge browser was still promoting links to MSNBC, but looking at Edge now, I see the links are to MSN.com which is a completely different thing and actually a Microsoft news portal.
Interesting the news channel is still called MSNBC though even though Microsoft doesn't have any ownership in it anymore.
NBC's chime was developed when it was owned by GE in the 1930s (the notes are G-E-C – General Electric Company). When GE sold its interest, that chime continued to be used.
GE later regained control of NBC, and once again sold the last of its interest to Comcast a few years ago. But the G-E-C jingle remains unchanged, the first audio trademark granted in the US.
Apparently this is folklore: https://en.wikipedia.org/wiki/NBC_chimes#%22General_Electric...