On the first trading day after Nintendo told investors how much it really owns of Pokémon Go, the company's share price plunged 17 percent in the Japanese market.

Nintendo's stock price still is up more than 60 percent compared to what it was before Pokémon Go's July 5 launch. Still, Nintendo's reminder of how much it owns of The Pokémon Company, and therefore the limited nature of its revenue from Pokémon Go, helped shave about $6 billion off the company's market capitalization.

Two weeks ago an analyst noted that Niantic Labs, The Pokémon Company (of which Nintendo owns 32 percent) and Nintendo jointly developed the app. However, app stores will also take a cut of any Pokémon Go revenue. The analyst estimated Nintendo itself only gets about 10 percent of that.

Nintendo also told investors on Friday that the financial forecast it made back in April already accounted for Pokémon Go and the upcoming Pokémon Go Plus peripheral — which Nintendo is developing and selling itself. That is, the craze notwithstanding, Nintendo said it is not changing its financial forecast — which called for net sales of 500 billion yen, down 0.9 percent from the previous fiscal year.

Pokémon Go has launched in North America (except Mexico), Europe, Australia and New Zealand and, most recently, Japan. Anticipation of the game's Japanese launch made Nintendo's stock the most traded in a single day over the past 16 years, and boosted the company's stock price about 25 percent during Pokémon Go's first week of release.