In a surprising and wholly unexpected Sunday announcement, Blizzard Entertainment owner Vivendi Games announced that it will be merging its assets and studios with those of Activision. In all, the deal is valued at $18.9 billion.

The new company, Activision Blizzard, is expected to have approximately $3.8 billion in pro forma combined calendar 2007 revenues and the highest operating margins of any major third-party video game publisher. On closing of the transaction, Activision will be renamed Activision Blizzard and will continue to operate as a public company traded on NASDAQ under the ticker ATVI.

Blizzard has posted an FAQ on its official site stating that neither its games, policies, not development process will be affected by the merger.