The penalty for the late filing of Form 1120S Schedule K-1 can vary depending on the specific circumstances and the amount of tax owed. However, generally speaking, the penalty for late filing of Schedule K-1 for Form 1120S is $195 per month or part of a month for each shareholder of the S corporation. The maximum penalty per shareholder is $1,950 per year. It's important to note that this penalty is subject to change and it's always recommended to consult with a tax professional or refer to the official IRS guidelines for the most accurate and up-to-date information.