AirAsia Bhd., Southeast Asia’s biggest budget carrier, and its affiliate AirAsia X Bhd., slumped in Kuala Lumpur trading Thursday. The number of shares changing hands set a record for the year.

AirAsia tumbled 9.9 percent to 1.82 ringgit, with 78.34 million shares changing hands. AirAsia X., the long-haul budget carrier and part of the group, closed at 23 sen, the lowest ever since the company began trading in July 2013. Trading volume in that stock surged to 80 million, the second-highest ever.

“It’s most likely foreign selling, if you look at the volume,” Kenanga Investment Bank Bhd. analyst Adrian Ng said by phone. “It could be due to the ringgit’s weakness.”

An e-mail sent to AirAsia’s public relations department wasn’t immediately answered. A phone call to Tony Fernandes, the chief executive officer of the group, wasn’t answered.

Tune Air Sdn. is the largest shareholder of Sepang, Malaysia-based AirAsia, controlling 19.1 percent of the stock, according to data compiled by Bloomberg. Tune Group Sdn. is the biggest shareholder of AirAsia X, with 10.2 percent. AirAsia held 7.9 percent of AirAsia X, according to Bloomberg data.

The stock of AirAsia, which uses Airbus Group SE single- aisle planes to fly across Asia, was the worst performer on the MSCI Emerging Markets Index Thursday. The FTSE Bursa Malaysia KLCI Index, the country’s benchmark, dropped 0.1 percent at the end of the day’s trading.

In 2001, Fernandes mortgaged his home in Kuala Lumpur to establish Tune Air with his partners. That same year, the group bought money-losing AirAsia from its owner, DRB-Hicom Bhd., then a Malaysian government-owned conglomerate. AirAsia X was set up in 2007 and flies internationally using Airbus twin-aisle planes.