SEMT Pielstick is a French diesel engine manufacturer based in Villepinte, France and owned by MAN Diesel, a subsidiary of MAN AG SEMT Pielstick was formed in 1988 when the business was acquired from GEC Alsthom by MAN and MTU, originally as a 50/50 partnership. MAN increased its shareholding in February 1998 and in December 2006 bought the remaining 33% of the shares held by MTU, thus making MAN the sole shareholder of SEMT Pielstick. The company has been renamed MAN DIESEL SA and trades under this name.