Since creating a corporate entity called Alphabet, it looks like Google is continuing to acquire Alphabet related domain names. According to a now public Whois record, Google, Inc. is showing up as the owner of Alphabet.net.
Jamie Zoch first reported the acquisition via Twitter, and he speculated that the company acquired Alphabet.net back in August. On July 31, 2015 (and prior to that), Alphabet.net was owned by a domain registrant based in Ohio. The Whois information went private around August 10th, and it just emerged from privacy on November 27.
The Alphabet.net domain name does not currently resolve, so I suspect the company acquired it for defensive reasons. At the beginning of October, I reported that Google had acquired the full alphabet .com domain name, abcdefghijklmnopqrstuvwxyz.com. That domain name does not resolve to a website either. The company also seems to be opportunistically buying other alphabet related domain names.
This morning, Shane Cultra reported that ABC.net is up for sale on Flippa, and it has a high bid of $17,000. The reserve has not been met on that auction listing. It will be interesting to see if the company goes after this domain name as well.
Alphabet uses ABC.XYZ for its corporate home page. Alphabet.com is owned by BMW, and it does not seem likely that the company would sell it. ABC.com is owned by the ABC television network, and I can not imagine that the company would sell the domain name to Google / Alphabet barring a major acquisition.