Not that surprising, and as someone else has said, on the back of the mobile news earlier this year, Nintendo's stock had probably become overvalued.
Investors were expecting Mario on smartphones by Christmas, despite the fact Nintendo had said that was unlikely to happen. The combination of the game being a Mii-driven app and something that's not coming out till March was bound to disappoint the people who jumped on board earlier this year expecting to make a quick buck.
A fall in share value is hardly a long-term disaster for Nintendo. Their stock is still well up on where it was 12 months ago, and with 5 smartphone titles coming in a 12 months period (not to mention Kimishima being very bullish about their profit expectations over the next few years) I think we'll be seeing investors jump back on board in 2016. Nintendo will concentrate on getting the launch of Miitomo and their new account service right.







