Trinseo PLC — Director's Dealing 2014

SEC Form 3 — Initial Statement of Beneficial Ownership

Issuer: Trinseo S.A. (TSE)
CIK: 0001519061
Period of Report: 2014-06-11

Reporting Person: Meisel Seth (Director, 10% Owner)

Holdings (Non-Derivative)

Footnotes

F1: Represents ordinary shares of Trinseo S.A. held by Bain Capital Everest Manager Holding SCA ("BCEM Holding") whose general partner is Bain Capital Everest Manager S.a r.l. ("BCEM"). All of the outstanding share capital of BCEM is held by Bain Capital Europe Fund III, L.P. ("Europe Fund III") and, in that capacity, Europe Fund III has the power to appoint the managers of BCEM. Bain Capital Investors, LLC ("BCI") is the general partner of Bain Capital Partners Europe III, L.P., which is the general partner of Europe Fund III. By virtue of these relationships, BCI may be deemed to share voting and dispositive power with respect to the shares held by BCEM Holding.

F2: (Continued from footnote 1) In addition to being the general partner of Bain Capital Partners Europe III, L.P., which is the general partner of Europe Fund III, BCI is the general partner of Bain Capital Partners X, L.P., which is the general partner of Bain Capital Fund X, L.P. BCI is also the managing general partner of BCIP Associates IV, L.P., BCIP Associates IV-B, L.P., BCIP Trust Associates IV, L.P. and BCIP Trust Associates IV-B, L.P. Mr. Meisel is a Managing Director of BCI. By virtue of the relationships described in this footnote, Mr. Meisel may be deemed to share voting and dispositive power with respect to the shares of Trinseo S.A. held by BCEM Holding. Mr. Meisel disclaims beneficial ownership of such securities except to the extent of his pecuniary interest therein.