By Maki Shiraki
TOKYO (Reuters) - Shares in Japan's Takata Corp (7312.T) slumped by a quarter on Thursday as more automakers considered no longer using its air bag inflators, casting further doubt on the future of the parts supplier at the center of a global recall crisis.
A day after Takata's biggest customer, Honda Motor Co <7267.T>, said it would stop fitting its cars with the company's air bag inflators, Mazda Motor Corp <7261.T> said it would drop Takata inflators containing ammonium nitrate from its new cars.
Japanese automakers Mitsubishi Motors Corp (7211.T) and Subaru-maker Fuji Heavy Industries Ltd <7270.T> also said they were thinking about switching away from Takata's inflators.
Air bag parts contributed 38 percent of Takata's total sales last year. The company reports its first-half results on Friday.
U.S. regulators say Takata's inflators use a chemical propellant they suspect causes the air bag to explode with too much force, spraying metal shards into the car. The inflators have been linked to eight deaths, all in Honda cars, and have led to the recall of more than 40 million cars worldwide.
"We will not use Takata air bag inflators which contain ammonium nitrate in our new cars," Akira Marumoto, Executive Vice President of Mazda, Japan's fourth-largest automaker, told reporters.
Earlier, Fuji Heavy CEO Yasuyuki Yoshinaga said: "We're thinking of not using Takata's inflators for future cars." He said Subaru may also look elsewhere for the inflators it needs to fix cars under recall as it was taking Takata too long to supply them.
Shares in Takata slumped 25 percent, or by their daily limit of 300 yen - to close at a 6-1/2-year low. In two days, some $330 million has been wiped from the company's market value.
The founding Takada family owns about 60 percent of Takata, while Honda holds 1.2 percent.
A Toyota Motor Corp <7203.T> executive said on Thursday the company continued to investigate Takata's air bag inflators and remained committed to using "higher quality" components. He did not elaborate.
On Wednesday, Nissan Motor Co <7201.T> said it would defer to U.S. regulators on actions related to Takata.
Takata said on Wednesday it would pay a $70 million fine imposed by the U.S. National Highway Traffic Safety Administration (NHTSA) in installments, and phase out - as ordered by NHTSA - the use of potentially volatile ammonium nitrate as a propellant in its air bag inflators.
($1 = 121.4700 yen)
(Reporting by Maki Shiraki; Additional reporting by Kentaro Sugiyama; Writing and additional reporting by Chang-Ran Kim; Editing by Ian Geoghegan)