You are taxed on the full amount of the net income generated by the S corporation.
However, the net income should exclude your "reasonable salary" as you should have taken that salary in the form of payroll (and, as a result, the salary would have reduced the S corporation's net income).
Therefore, the $50,000 in net income (in your example) would be taxable to you (as passed through on your K-1), but would not be subject to self-employment tax.
Question: With respect to the hypothetical $150,000 you took as your salary, did you file 941s for withholding, etc., and issue yourself a W-2?
