Form 1120S
A corporation or other entity must file Form 1120-S if (a) it elected to be an S-corporation by filing Form 2553, (b) the IRS accepted the election, and (c) the election remains in effect.
An LLC can file a Form 1120-S only if it has filed Form 2553 to elect to be treated as an association taxable as a corporation which is electing S-Corporation status.
See also section Form 1120.
Pages in the Form 1120S topic group