Sega corporate director Masanao Maeda syas Mario & Sonic at the Olympic Games will sell over 4 million copies.

However, Masanao Maeda declined to give a time period for these expected sales at the TGS, but it is interesting to note that 4 million sales would account for 20% of Sega’s sales from the 2006/2007 financial year.

Mario & Sonic at the Olympic Games is the first time that Mario and Sonic will appear in an official game, and will see them competing against each other in Olympic events. The game is an official product of the Beijing 2008 Olympics.

(source)