The SEC's Division of Enforcement opens hundreds of investigations a year, and the overwhelming majority of them are resolved long before a judge ever sees the file. This guide explains the whole life cycle: where cases come from, what separates an informal inquiry from a formal order, how the subpoena and testimony powers actually work, what the SEC does and does not get to see of your privileged material, and how to think about the Wells notice and the Wells submission that follows it. It then walks the remedies — injunctions, disgorgement after Liu v. SEC and the NDAA, the three-tier civil penalty structure, officer-and-director bars, and industry bars — and the forum question after SEC v. Jarkesy stripped the agency of its in-house penalty power in fraud cases. Along the way it covers cooperation credit under the Seaboard factors, the mechanics and pathologies of the neither-admit-nor-deny settlement, coordination with the Justice Department in a parallel criminal case, the five- and ten-year limitations rules, and the private class action that arrives the day the SEC's order hits the wire. The through-line is strategic: every early decision in an SEC investigation — the litigation hold, the internal investigation, the first document production, the first witness — narrows or widens the options available at the end.