UPDATED: Activision Blizzard’s stock price fell as much as 6% Tuesday in early trading before bouncing back and reaching all-time highs, as investors digested the mammoth size of its proposed acquisition of mobile-gaming leader King Digital Entertainment.

Activision Blizzard, whose core business revolves around console and PC titles, said late Monday that it had agreed to acquire King in a deal valued at $5.9 billion. Activision will use approximately $3.6 billion of offshore cash on its balance sheet to fund the deal, along with $2.3 billion in debt financing under existing credit agreements.

Also Monday, Activision posted better-than-expected financial results for the third quarter of 2015, and raised expectations for full-year 2015 revenue and earnings.

The companies touted the combo as bringing together Activision’s strong base of action and role-playing titles, such as “Call of Duty” and “World of Warcraft,” together with King’s top-grossing mobile games such as “Candy Crush” and nearly 500 million monthly active users.

Investors pushed Activision Blizzard shares down in early trading to as low as $32.39 per share, down 6.3% from Monday’s $34.57 closing price. Around 10:15 a.m. ET, shares had rebounded into positive territory, and by mid-day climbed as high as $37.80 per share (up 9.3%) — an all-time high for the company. [UPDATE: Shares closed Tuesday at $35.82, a record high and up 3.6% for the day.]

On Monday, Moody’s Investors Service upgraded Activision Blizzard’s debt rating to investment-grade, citing the company’s strong position in gaming and saying its long-term outlook is stable with the planned King acquisition.