Tesla, in an offer to acquire SolarCity, appears to be the first to announce a major proposed acquisition by a blog post. Since an 8-K was also filed, it can’t be sole proof that social media is a recognized distribution channel for Regulation FD. But dissemination was nonetheless rapid, with the first news apparently appearing on Twitter at about 4.11 pm, the 8-K being filed at 4.13 pm, and the first Wall Street Journal e-mail alert being received at 4.58 pm (all times Central).

There had to be some advance coordination between the parties, because SolarCity filed an 8-K almost simultaneously. The exhibit includes an email from SolarCity’s CEO, in which he wisely advises employees not to comment on social media.

The Tesla 8-K also discloses that Tesla adopted an exclusive forum by-law the day before the acquisition was announced.