TOKYO—Mitsubishi Motors Corp. said Friday it manipulated fuel-economy data on more car models than previously reported and will book a ¥50 billion ($479.5 million) one-time loss in the current financial year, more than tripling the estimated cost of the scandal.

Mitsubishi said Friday it had falsified data to make mileage appear better on 20 models sold domestically between 2006 and 2016. The company’s previous reports focused on models currently on the market.

...