Police searched the Lottery Online Company premises in Bangkok's Watthana district on Monday as part of an operation against the accumulation of lottery tickets for overpriced resale.
Police and officials of the Government Lottery Office (GLO) searched the company's offices on the 21st floor of SSP Tower 1 building on Sukhumvit 63 Road.
They were accompanied by Seksakol Attawong, a vice minister of the Prime Minister's Office.
He said the company bought lottery tickets from small vendors who had ticket quotas with the GLO, and resold them at more than the official price.
Monday's search followed a similar visit to the premises of another government lottery middleman company, Mungkornfa, in Nonthaburi and Loei provinces on Friday.
Officials were taking action to suppress the practice, Mr Seksakol said.
About 4,000 small-quota vendors of lottery tickets would face disciplinary action. Some would be treated as witnesses in the case, he said.
Assistant police chief Pol Lt Gen Prachuap Wongsuk said there were millions of government lottery tickets found at the premises of Lottery Online. They were being resold via a website and an app for at least 95 baht a ticket, well above the official retail price of 80 baht.
Evidence was found of ticket transactions of more than 100 million baht per lottery draw. The vendors involved who had lottery ticket quotas with the GLO would lose their quota, Pol Lt Gen Prachuap said.
It was not yet clear if the company sold the same lottery tickets to more than one buyer, he said.
The tickets were seized.
No charges have been laid to date. Officials said they wanted to discourage small vendors from supplying their tickets to middlemen, who resell them at high prices.