Nintendo stock fell by 1.8% on Wednesday (June 6) and a further 0.99% today, reports CVG.
Nintendo's stock rose by 3% prior to the E3 Gaming Expo, but dropped back after what was perceived to be a lacklustre E3 press conference on Tuesday (June 5).
In an attempt to get investors on board with the Wii U, Nintendo's Satoru Iwata said: "The device has to win support from within the family.
"We have to show the benefits of the Wii U device from different angles in order to reach the mother, the father and the children."
Earlier this week, Nintendo announced Wii Fit U, SiNG and Nintendo Land, while showcasing Super Mario Bros Wii U and Pikmin 3.
> 'Pikmin 3' officially unveiled by Nintendo
> Wii U to introduce video streaming
> 'Arkham City: Armoured Edition' unveiled
> 'Mass Effect 3' confirmed for Wii U
> 'Wii Fit U' announced by Nintendo at E3
> 'SiNG' announced for Wii U
> 'Nintendo Land' announced for Wii U at E3
> 'New Super Mario Bros 2' dated for US
> E3 2012: Nintendo live blog, video stream
Watch a trailer for Super Mario Bros Wii U below: