I know this is a First World gripe, but why are "flow-through entities" allowed to send out their K-1 forms, which you need in order to fill out your tax return, AFTER the April 15 tax deadline? The deadline for every tax form and statement from banks, employers, and so forth is Jan. 30; why not K-1s?
Every year I get all my tax paperwork together early, and then I wait and wait for the stupid K-1s to show up in the mailbox. As of this writing, on April 15, I have not received a single one.
The only completely safe option is to apply for an extension to file your tax return. Or, of course, to ditch the investment completely.