This carmaker just slumped 33% (Hint: it's not Volkswagen)

Worst is yet to come for airbag manufacturer Takata
Worst is yet to come for airbag manufacturer Takata

Revelations that Mitsubishi Motors cheated on fuel economy tests have wiped out a third of the company's stock price in just two days.

The Japan-based automaker admitted on Wednesday afternoon that it had illegally rigged fuel economy tests affecting hundreds of thousands of vehicles.

Investors pressed the sell button as news broke and continued unloading shares during Thursday's trading session. The stock has now shed $2.5 billion in market cap and is sitting at a record low.

There are signs that more pain is to come. Japanese authorities raided Mitsubishi's offices on Thursday and the country's chief cabinet secretary said the company's actions were "extremely serious."

"This is a case of manipulation of test data which undermines consumers' trust, and it should not have happened," Yoshihide Suga said at a news conference.

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The rigged tests affected four minicar models sold only in Japan, Mitsubishi said. It supplies two of the models to its bigger counterpart Nissan (NSANF).

Mitsubishi is halting production and sales of the cars. It said it had sold 157,000 units of two of the models, and supplied 468,000 units of the other two models to Nissan.

Mitsubishi said it would "sincerely respond" to customers who bought the cars and would also discuss compensation with Nissan. The affected models are sold under the names eK Wagon, eK Space, Dayz and Dayz Roox.

The Mitsubishi announcement follows a huge scandal that rocked German auto giant Volkswagen (VLKAF) last year after it admitted rigging diesel engine emissions tests in America and Europe. VW's stock tanked 31% in the two days after news of its cheating first broke.

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Other automakers have been penalized in recent years for putting a rosy spin on fuel economy figures.

Korean carmakers Hyundai (HYMTF) and Kia agreed to pay a combined $100 million fine in the U.S. in 2014 for overstating fuel economy estimates for many of their vehicles. They also had to refund customers for the difference in estimated fuel costs.

That same year, Ford (F) said it would compensate owners of about 200,000 U.S. vehicles after discovering the cars' gas mileage was overstated.

-- Jethro Mullen, Alanna Petroff and Junko Ogura contributed reporting.

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