Only three firms will compete for concessions to run duty-free shops at Samut Prakan's Suvarnabhumi airport, after two potential bidders dropped out of the race.
The three remaining firms are King Power Duty Free Co, Bangkok Airways (BA) Plc, and Royal Orchid Hotel (Thailand) Plc, or ROH.
Meanwhile, Minor International Plc (MINT) and Central Department Store Co decided to opt out of the process.
"As of the deadline yesterday, only King Power, BA and ROH had submitted their bid envelopes," said the senior executive vice-president of Airports of Thailand Plc (AoT), Wichai Bunyu.
Mr Wichai said it is possible MINT pulled out of the race because it had no direct experience in duty-free operations, or was unable to find business partners.
He said he cannot speculate on why Central Department Store did not submit their bid envelope.
However, he said the AoT is not worried by their decision to opt out.
"Three bidders are enough, and each firm has fully met our criteria," Mr Wichai said.
The companies will be invited to present their technical proposals on Monday, and the AoT is expected to be able to announce the winner by next Friday, he said.
AoT's senior executive vice-president said each firm will be scored on two aspects.
The technical aspect of the proposals has a weighted percentage score of about 80%, while the remaining 20% score will be based on the quoted prices, he said.
"We need to give more weight to the technical aspect since we need to be sure the private company is capable of doing this business," said Mr Wichai.
Vitavas Vibhagool, CEO of Grande Asset Hotels and Property Plc (GRAND), a major shareholder of ROH, expressed confidence in his firm's bid.
He said the company has experience in real estate development and is a partner of a duty-free operator from the United Kingdom, which has a network of more than 600 stores across the globe.
In relation to another contract to develop Suvarnabhumi airport's other commercial spaces, King Power Suvarnabhumi Co, MINT and Central Pattana Plc (CPN) submitted bid envelopes on Wednesday.
The Mall Group Co, which earlier bought the envelope, did not show up for the process.
In a related development, two companies and two consortiums have expressed their interest in participating in the bidding process for the concession to run duty-free shops in Phuket, Hat Yai and Chiang Mai, according to the AoT.
The firms consist of King Power Duty Free, Central Department Store, a BA-led consortium and a ROH-led consortium.
They are scheduled to submit their bid envelopes by June 4.