Avis Budget Group (CAR) announced after market close yesterday that it had completed its $500 million acquisition of car-sharing company ZipCar, which originally was announced in early January. Today, ZipCar CEO Scott Griffith told employees that he was handing the reins over to chief operating officer Mark Norman.

The news was first reported by Scott Kirsner, via a series of tweets:

It’s obviously not unusual for leadership changes after a merger, but it’s a bit odd that neither Avis nor ZipCar announced that such a move was coming (such as in yesterday’s press release). Instead, the news leaks out in a Friday afternoon memo. Not exactly a gallant send-off for someone who 10 years ago agreed to take over a tiny start-up, and helped it trail-blaze what is now commonly known as the “sharing economy.”

Maybe Griffith wanted to walk away quietly, so as not to freak out ZipCar customers who already are a bit nervous about the big new corporate parent. But Avis could have pulled out its horns for at least a tiny bit of fanfare (you know, beyond the $500 million)…

UPDATE: Fortune has now obtained a copy of Griffith’s letter to employees, which is posted below:

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