TimkenSteel Corp. – TMST: Involvement in a Previously Undisclosed SEC Investigation Now Appears Over – Removed from Watch List – Documents Received. Recently received documents show the undisclosed SEC investigation of TimkenSteel that we’ve been tracking since Sep-2017, was part of a broader probe into use of non-GAAP metrics. An excerpt showing the particular questions the SEC had about TMST’s filings appears in today’s report.