March 15, 2024
Electing large partnerships – File a previous calendar year return (Form 1065-B). Provide each partner with a copy of Schedule K-1 (Form 1065-B), Partner’s Share of Income (Loss) From an Electing Large Partnership. This due date is effective for the first March 15 following the close of the partnership’s tax year. If you want an automatic 6-month extension of time to file the return, file Form 7004. Then file Form 1065-B by September 15.