S Corporation Tax Extension Deadline 2024. If an s corporation has successfully filed for an extension, the new due date would be the 15th day of the ninth month following the end of the corporation’s tax year. S corps and partnerships can still get an extension on march 15, and the last day for c corps to file for an extension is april 15.

What irs tax forms do s corps file? The tax extension deadline for businesses that file as s corporations or partnerships is march 15, 2024.