The semiconductor sector in Europe had a bad week this week. STMicroelectronics led the declines in that sector. The value of its shares lost almost 10 percent on the week after reporting losses in the first quarter.

Other semiconductor manufacturers also did badly, with ASML down 7.4 percent for the week, while Infineon was down by 7.5 percent. STMicroelectronics did not suffer the largest losses of the week however.

That distinction came in the pharmaceuticals sector, where Novo Nordisk lost 14 percent after it warned of a possible three-year delay before it will be able to implement a new use for one of its products.

Not all stocks declined on the week, however, Dassault Systems, largest maker of computer-aided design software in the world, was up after releasing a positive first-quarter earnings report. Dassault was up 5.1 percent for the week.

Overall, the European equities market was down for the third week in a row, as the FTSE Eurofirst 300 ended the week down by 1.2 percent despite a small rally Friday, when it closed at 1059.7.