Tata Motors managing director Karl Slym, 51, died early Sunday at the Shangri-La Hotel in the Thai capital where he was attending a board meeting, the company has confirmed.

"Initially, we can only assume that he committed suicide", Thai Police Lieutenant Somyot Boonnakaew told AFP.

"The window was small and he had to try hard to get through it."

The apparent suicide letter, found at the scene, has been sent for analysis to confirm it was written by Slym, he said.

Police believe his wife was in the room at the time of his death but said she was too "shocked" to answer questions on Monday.

"She still cannot accept what has happened," said Somyot, adding the executive's body was with forensic scientists.

Slym's body was found by staff on a fourth floor balcony at the five-star $200-a-night hotel, which said the "circumstances of the accident are under review by authorities."

On Sunday the carmaker said he had died in a fall, while Indian press reports said Slym may have lost his balance and plunged to his death.

The Briton had been Tata's managing director since joining the country's leading car making group in 2012.

In November Tata Motors, part of the giant steel-to-software Tata Group, said its quarterly net profit surged by 71 percent on the back of booming sales of its British luxury marque Jaguar Land Rover.

Slym had led Tata's operations in India and international markets, excluding the Jaguar and Land Rover businesses.

At midday trading in Mumbai, the stock was down 16 rupees to 354.50 rupees, a fall of 4.32 percent while the main Bombay Stock Exchange index was down 356.75 points at 20,776.81.

Explaining the stock drop, an analyst in Mumbai said the death of the Stanford University graduate could raise fears over the "timeline for new projects."

"In addition, the market is down today in general. So the stock is getting hammered," said an analyst who did not wish to be named.

Slym had previously been executive vice president of SGMW Motors, China, a General Motors joint venture, and been president of General Motors in India.

In a statement late Sunday Tata chairman Cyrus P Mistry paid tribute to "valued colleague" Slym.

(AFP)