Vietnam-focused private equity firm PENM Partners has sold a 30 percent stake in European Plastics Window Company—a Vietnam-based door, window and partition manufacturer that markets under the Eurowindow brand—to Japan-based sliding door manufacturer Bunka Shutter. PENM Partners originally invested in the company in 2007 and made a follow-on investment in 2011, both structured through its fund Private Equity New Markets I. Financial details of the transaction were not disclosed.