Blackstone (BX) and Tinicum received European Commission approval to jointly acquire PennAero and TriMas' (TRS) Aerospace unit, the Commission said Tuesday.

The EC said it cleared the deal under its merger rules, after determining that the transaction does not pose competition issues because the businesses involved have "negligible" operations within the European Economic Area.

Shares of Blackstone were down more than 4% in recent Tuesday premarket activity.