Yo, Dumbphuck, there is NO SEC statutory requirement of a black out period. If there was a blackout period -- and XIN has talked about one a few times -- then it was only imposed by XIN itself.
Specify when you think the blackout period applies: Which days? Which weeks? Where did you learn that information? Do you believe it's an SEC Rule? If yes, which one?
Most companies don't bother with blackout dates for RePurchase. They get around the Insider trading problem by completely automating the process: "We will RePurchase the maximum amount of shares possible under SEC Rule 10b-18, each day of each week until the $20 million is spent."
Do you suppose XIN to be too stupid to adopt a plan like that?
Buybacks are only restricted to intra-days unlike insider trades, which should have been blacked out. Regardless, both are safe harbor provisions and unlikely but not impossible under all circumstances.