Methode Inflated Share Price Before 70% Slide, Investor Says

Methode Electronics Inc. concealed major problems in its automotive parts segment before a series of revelations led to a yearlong 70% stock price decline, including the stock’s largest single-day drop, an investor alleges.

The product maker misleadingly said it would be able to replace a lost contract with General Motors Co. for automotive center consoles with new business, according to the complaint filed Monday by a Cape Coral, Fla., municipal retirement plan. The investor filed its proposed class action in the US District Court for the Northern District of Illinois.

Methode also failed to disclose “significant, ongoing operational inefficiencies” that ...