From dmertz
20 Forms 1099-R is the limit.
If you have multiple Forms 1099-R that show no tax withholding in box 4, have the same code in box 7 and the marking of the IRA/SEP/SIMPLE box is the same, these can be summed into a single Form 1099-R entry since, under these circumstances, the details of the Forms 1099-R are not transmitted with your e-filed tax return. Only the totals are included on Form 1040 lines 15 and 16 or Form 1040A lines 11 and 12.
(Some payers that hold multiple investments in a single retirement account unnecessarily issue a separate Form 1099-R for a distribution from each investment within the account rather than issuing a single Form 1099-R for the entire account.)
