French telecom and media group Vivendi said on Sunday it will merge its video games unit with Activision Inc in a $9.85 billion deal that combines the hit Guitar Hero and World of Warcraft franchises under one roof.

The complex deal will give Vivendi a 52 percent stake in a new industry giant called Activision Blizzard with annual revenue of $3.8 billion, rivaling that of Electronic Arts Inc, the world's biggest independent game publisher.

Activision, which is riding high on the success of games such as Guitar Hero, Call of Duty and Tony Hawk, has lacked an offering in the online role-playing area, which is dominated by World of Warcraft from Vivendi's Blizzard Entertainment.

This turns Activision into an EA-like company. It turns them far more global, puts them in China, where they haven't been, and in (online games), where they haven't been, said Michael Pachter, an analyst with Wedbush Morgan Securities.

The deal values Activision at $27.50 per share, or a 24 percent premium to its Friday closing price.

Vivendi will contribute its Vivendi Games business, which it valued at $8.12 billion, and provide $1.73 billion in cash for the 52 percent stake in Activision Blizzard. These terms value the combined company at $18.9 billion.

Activision Blizzard will operate as a publicly traded company. The news surprised some given Activision's surging sales and profit.

This company didn't look like it was positioning itself for a sale, Mike Hickey, an analyst with Janco Partners, said of Activision. They've had a phenomenal year and everyone likes to go out on top, so maybe that's what they're doing.

Activision and EA have broadened their offerings by buying privately held game makers. In October, Activision bought Britain's Bizzare Creations, a maker of racing games, while EA bought BioWare/Pandemic, a creator of role-playing and action games, in a deal worth up to $855 million.

Blizzard was an appealing partner because of their culture, their willingness to provide capital. There was personal chemistry and a shared philosophy -- Vivendi is focused on shareholder returns, Activision Chief Executive Bobby Kotick told Reuters in an interview.

Kotick will stay on as CEO of Activision Blizzard, with Vivendi Games Chairman Rene Penisson becoming chairman. Activision Co-Chairman Brian Kelly will also be co-chairman of the new company.

The deal will immediately boost Activision's earnings in the first year after closing, and will be slightly accretive for Vivendi's stockholders, the companies said.

Activision Blizzard said it expects pro forma operating income of $1.1 billion and pro forma earnings per share of more than $1.20 a share in calendar year 2009.

Within five business days after closing the transaction, the new Activision Blizzard will launch a $4 billion all-cash tender offer to purchase up to 146.5 million Activision Blizzard common shares at $27.50 per share.

The tender offer will be funded by Activision Blizzard's cash on hand at closing, including the $1.7 billion in cash received from the Vivendi share purchase. In addition, Vivendi has agreed to buy more newly issued shares for up to an additional $700 million, the proceeds of which would also be used to fund the tender offer.

Any remaining funds required to complete the tender offer will be borrowed by Activision Blizzard from Vivendi or third-party lenders. If the tender offer is fully subscribed, Vivendi would own about 68 percent of Activision Blizzard.

On Friday, Activision's stock closed on Nasdaq at $22.15, up 18 cents, or 0.8 percent. The shares have risen nearly 30 percent over the past year, fueled in large part by the success of Guitar Hero games.

(Editing by Jan Paschal, Phil Berlowitz)