I'd reinforce Boofinator's speculation about dividends. If you buy a mutual fund right before the dividend date, the 60 day clock starts counting to decide if those dividends are qualified or not. If anything, Feb 15th probably isn't enough time for the most extreme case of buying right before the record date for the dividend.
So if you're waiting on 1099-DIV, or a combined 1099 that includes 1099-DIV, it might be about the dividends being qualified (held 60 days plus other rules) versus not qualified (and so taxed at a higher rate).
In addition, if you sell an asset - say a mutual fund - on Dec 31st at a loss, that offsets your capital gains. But if you buy that same mutual fund 3 weeks later, you have retroactively turned that prior event into a "wash sale", and you cannot claim a loss. So form 1099-B could also be impacted, as wash sales require a 30 day wait to see what happens.