Complex sentence: Swordfish Studios was acquired by Vivendi Games in June 2005, becoming a fully owned studio of Sierra Entertainment, then acquired by Codemasters on 15th November 2008 after an agreement with Activision Blizzard.
Split into simpler sentences: Swordfish Studios was acquired by Vivendi Games in June 2005, and became a fully owned studio of Sierra Entertainment. As of 15th November 2008, Swordfish Studios was acquired by Codemasters after an agreement with Activision Blizzard.