Shares in Nintendo have fallen 7.1% at the end of trading on the Tokyo Stock Exchange on Monday, December 19th as investors show concern over Super Mario Run's performance.

The auto-runner is Mario’s big debut on mobile and has got off to a strong start. App data firm App claims the game raked in $4 million in its first day from 10 million downloads.

In its first three days, it is estimated the title managed to garner more than 37 million downloads.

It was the top grosser in numerous countries across the globe, a particularly impressive feat for the free-to-start title, which charges $9.99 to unlock the full game.

Shares trip up

But investors seemingly remain unconvinced by the game’s performance and potential.

On December 16th, a day after launch, Nintendo’s shares closed 4% lower from the start of the day. Shares then fell by 7.1% on Monday, December 19th.

At this early stage, Super Mario Run has reviewed poorly compared to other top grossers on the App Store.

The title also offers a premium price point rather than a free-to-paly experience like Pokemon GO, something investors are also seemingly unconvinced by.

Super Mario Run's free-to-start strategy is expected to be used in Nintendo's future mobile titles such as Animal Crossing and Fire Emblem.

According to The Wall Street Journal, a Nintendo spokesperson has also said the company doesn’t plan to release additional free or paid content for Super Mario Run, such as new levels and characters.