A local labor standard office has concluded that the suicide of a worker in his 50s at Nomura Real Estate Development Co. in 2016 was caused by overwork, sources close to the matter said Sunday.

Although the real estate firm applied the discretionary system, rewarding workers based on fixed overtime work hours instead of actual hours worked, to around 600 workers, including the man, many of them were engaged in business operations that are not supposed to be treated under such a working style.

The discretionary system is allowed to be applied to workers engaging in two types of work — the specific specialty type, such as lawyers and reporters, and the management planning type, including those who engage in surveys and analysis.