Disgorgement of increased profits (or reduced) losses is a typical civil remedy offered by the SEC in such cases.

Securities Exchange Act of 1934, §§ 78u-2(e) and 78u-3(e).

78u-2(e): Authority to enter order requiring accounting and disgorgement: "In any proceeding in which the Commission or the appropriate regulatory agency may impose a penalty under this section, the Commission or the appropriate regulatory agency may enter an order requiring accounting and disgorgement, including reasonable interest. The Commission is authorized to adopt rules, regulations, and orders concerning payments to investors, rates of interest, periods of accrual, and such other matters as it deems appropriate to implement this subsection."

78u-3(e) is similar.

http://en.wikipedia.org/wiki/Disgorgement_(law)

The (presumed) intent is to remove the incentive for others to do this, which a fixed or capped fine would not accomplish (as you observed).