(Bloomberg) -- Zenrin Co. plunged the most in three years in Tokyo amid speculation that Japan’s biggest mapmaker has ended its relationship with Alphabet Inc.’s Google.

The shares fell as much as 13 percent to 2,576 yen on Friday, the biggest intraday decline since June 2016. Japanese users took to social media to complain about the sudden deterioration in the quality of Google Maps in the country, and pointed out that a previous copyright attribution to Zenrin has vanished from the fine print at the bottom of the screen.

On March 6, Google announced on its Japanese blog it will roll out a new version of its maps for the country, but that post made no mention of Zenrin. A spokeswoman for Zenrin declined to comment, and no one was immediately available for comment at Google’s Tokyo offices.

Legal notices for Google Maps and Google Earth available online continue to state those products use mapping data from Zenrin. And the Japanese company’s own website still lists a service selling access to the Google Maps platform.

To contact the reporters on this story: Pavel Alpeyev in Tokyo at palpeyev@bloomberg.net;Yuki Furukawa in Tokyo at yfurukawa13@bloomberg.net

To contact the editors responsible for this story: Robert Fenner at rfenner@bloomberg.net, Edwin Chan

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