Nintendo revealed in a new document that they will be acquiring up to 9,500,000 treasury shares tomorrow, and after an announcement on January 29th will gain up to 10,000,000 shares:

While this sort of business deal might sound strange or alarming, it's a rather normal business move that helps to keep stock prices stable and investors happy, as their own shares don't plunge in value. It's also a way for Nintendo to safeguard their company from a hostile takeover.

The shares come from Yamauchi heirs, who are letting go of some of them to pay for inheritance tax.