Nokia’s legal department is going to have a busy summer. Only a day after Nokia went on the offensive and filed lawsuits against HTC, RIM, and ViewSonic for patent infringements, a dissatisfied shareholder filed a class-action lawsuit against the struggling mobile company.

Robert Chmielinski filed a class-action lawsuit against Nokia and its CEO Stephen Elop and CFO Timo Ihamuotila in U.S. District Court for the Southern District of New York, claiming that the company and its executives misled shareholders. Specifically, the company committed fraud by telling shareholders that the Windows Phone platform would put an end to Nokia’s falling position in the smartphone market.

But since when did an optimistic outlook on a corporate bet equal fraud? According to the plaintiff, the key is that executives knew they were making misleading statements in order to artificially inflate the price of Nokia securities.

“During the Class Period, defendants had both the motive and opportunity to conduct fraud. They also had actual knowledge of the misleading nature of the statements they made or acted in reckless disregard of the true information known to them at the time,” the suit documents assert.

The lawsuit cites Nokia’s $1.7 billion Q1 earnings loss as evidence that Windows Phone failed to reverse the handset maker’s slide. It further claims that Nokia mismanaged the Lumia 900 release by shipping the device with a glitch, which forced the company to offer a $100 refund to customers.