By the 15th day of the 3rd month following the close of its tax year. A second extension is not available. Penalties for late payment or late issuance of K-1s still apply. An S corporation generally does not pay tax at the corporate level. If the S corporation was previously a C corporation, the S corporation may be liable for tax on excess net passive income, certain capital gains, or built-in gains.
Shareholders are responsible for payment of estimated tax on their personal returns.
The S corporation must pay estimated tax payments if corporate level taxes apply. No Double Tax On Profits An S corporation conducts business as a corporation, but is taxed in the same manner as a partnership. A major advantage of an S corporation is that income passed through to shareholders avoids the double taxation that occurs with a C corporation. A corporation can elect S corporation status by filing Form 2553, Election by a Small Business Corporation. Limited to 75 shareholders.