Heading into the last few trading minutes of the domestic session, MBS are a quarter point off their afternoon highs (100-29 vs 101-05 in Fannie 3.0s).  Normally, that's enough of a gap for some lenders to consider negative reprices, but that assumes the lender in question based rates on the very highest possible trading levels.

Not only that, but most rate sheets are still looking fairly conservative compared to pricing that's still intact.

So we find ourselves in the precarious position of having several lenders that would still be justified in improving rate sheets while we can imagine a scenario where a sadistic lender or two is considering a negative reprice.  Best bet would simply be to treat this as the opportunity to lock if you were planning on locking today, especially if your lender already put out a positive reprice.