Just got mine. Statement closed two weeks ago.
Thanks @K-in-Boston! I just got the Premium Rewards and this credit was on my statement. I was confused at first, since they never sent me an email about it as far as I can tell. But I remembered seeing this thread on My Fico, so that it explains it! A very nice little "extra" for their members.
So.... I just got this credit today. I had a $12 food charge in August from a vendor that I haven't been to since January (and I'm not even sure I used a credit card that day, but I suppose I did). I called BoA to get it removed, so they credited the $12. I just got the statement credit of $50 this morning, so I'm currently sitting at -$50 balance. I wonder if they'll take some or all of it back until I actually spend $50?