By mid-afternoon Nintendo's stock had climbed 8.1 percent to 614,000 yen ($5,095), adding to a 3.5 percent gain made on Wednesday after its earnings announcement.
Nintendo lifted its annual outlook above market expectations after quarterly operating profit more than tripled, as its strategy to expand the gaming population to women and the elderly paid off handsomely.
Offering innovative and easy-to-play games, the company's DS handheld player and Wii console have outsold rival machines, such as Sony's PlayStation 3 and Microsoft's Xbox 360, in recent months.
Its market value now stands at $72 billion, outstripping Sumitomo Mitsui Financial Group, NTT (Nippon Telegraph and Telephone), and Honda Motor, which had placed higher in the rankings only a day before. Nintendo shot past Sony last month.
The Kyoto-based company revised up its operating profit forecast by 37 percent to $3.1 billion for the year to March 2008, topping a consensus of a $2.53 billion profit in a poll of 20 analysts by Reuters Estimates.
It also lifted its annual dividend forecast to 960 yen from an earlier estimate of 700 yen.
Nintendo's DS lets users control play with a stylus instead of manipulating a keypad, while the Wii, which competes with Sony's PlayStation 3 and Microsoft's Xbox 360, comes with an unusual motion-sensing controller that can be swung like a bat or a sword.
The creator of such game characters as Mario, Zelda and Donkey Kong raised its sales forecast for the Wii by 18 percent to 16.5 million units for the current business year, while lifting its DS sales target by 18 percent to 26 million units.