About 36 per cent of Thailand's corporate equity is concentrated in the hands of just 500 people, highlighting wealth inequality in the country, a study from the Bank of Thailand's research institute shows.

Each of these 500 on average amasses 3.1 billion baht (S$140 million) in company profits annually, according to the report by the Puey Ungphakorn Institute for Economic Research. In contrast, the average yearly household income is about US$10,000 (S$13,700).

Thailand's private sector is dominated by tycoons at the helm of sprawling conglomerates. The gap between the well-off and the rest in a population of 69 million is among the challenges for the economy, according to the Word Bank.

Dr Krislert Samphantharak, author of the study and executive director of the Puey Ungphakorn Institute, said: "Magnates arise in Thailand from institutional factors that privilege certain businesses."

The institute said Thailand needs to promote competitiveness to reduce profits from monopoly power, and bolster entrepreneurship to help create a more equitable distribution of corporate wealth.

The research is based on an analysis of Commerce Ministry data on the 2.1 million shareholders in Thai firms in 2017. Dr Krislert said the study was funded by the University of California San Diego, where he is an associate professor at the School of Global Policy and Strategy.

The Thai government is trying to tackle inequality by boosting welfare handouts for the least well-off.

But the perception of a growing divide exacerbated by an economic slowdown is one of the nation's biggest political fault lines.

BLOOMBERG