The three - Charoen Pokphand Group (CP), Central Group and Thai Beverage (ThaiBev) - among the country's richest business groups, are said to have expressed interest in buying Tesco's assets in Asia.
Tesco is looking for a way to raise funds following the crisis over its accounting practices that led to a £263 million (13.8 billion baht) profit overstatement.
Tesco's chief executive Dave Lewis recently told the media that the company was considering several options to pull itself out of the biggest crisis in its history, including a sale of all assets globally, a sale of its business in Asia and raising capital through partnership deals.
A foreign banker who asked to not be named said Tesco appears not to have decided yet which option it would take.
"It could take some time for Tesco to finalise the best option, probably in February at the soonest," said a foreign banker.
According to another banker many international and local banks here are approaching the three potential buyers in a bid to be involved, either as financial advisers or more importantly as lenders, in what would be one of the biggest deals of the year.
Of the three candidates, a source said Central seemed to be the strongest in terms of capital, given its low level of debt and high capacity to borrow capital for new investment.
The CP Group is said to be highly leveraged while ThaiBev borrowed large amounts recently for expansion that included the purchase of the Singapore company Fraser and Neave.
Tesco's Asian assets include Tesco Lotus in Thailand, and operations in South Korea and Malaysia. The Asian operations are Tesco's most profitable and this could be a major factor for the company to consider the other options.
Tesco's assets in Thailand are estimated to more than B200 billion, while the South Korean assets are slightly lower than Thailand's. The Malaysian operation is the smallest in Asia.
People familiar with CP said the group would wait for Tesco's decision. However, Tesco's Thai assets may not suit CP's strategy after it bought Siam Makro for B188 billion. The purchase strengthened its Thai retail business to include 7-Eleven and hypermart Makro.
"CP has seen its operation here is quite strong; it may not worthwhile to pay massive money for Tesco in Thailand only. But the operation overseas would well suit the regional expansion strategy," said people close to the group.
"If CP invests in Tesco UK, its policy is to have at least 20 per cent shares in the company," sources added.
But finance is a point of concern for CP as it has spent a lot lately on acquisitions. Apart from Siam Makro, it also bought Ping An and it will need to spend more to buy the small Thai bank, LH Bank, if they can settle a price with the seller, Land and Houses Plc, a local banker noted.
A retail industry source views Central has having the most potential to buy the Thai operation, Tesco Lotus chain of superstores, to complement Central's retail business network.
For Chaoren Sirivadhanabhakdi, Tesco Lotus will be a big entry ticket to becoming a leading retailer immediately.
A retail industry source agrees that both CP and Central would look at Tesco's Asian operations rather than Thai assets only.
"For Central, it is almost a "must have" as it has done the least in business in Asia and Asean," said the source.
A foreign investment banker said that apart from Thai business groups, Hong Kong-based Dairy Farm, Japan's Aeon, Jardine Group and US retailer Walmart are all interested in acquiring Tesco's business.
Of these, Walmart is by far the strongest, with the ability to either buy out Tesco globally or being a partner of Tesco UK.
The three potential Thai buyers and Tesco Lotus have all refused to comment about the matter.
However, Ek-Chai Distribution System Co, the operator of Tesco Lotus in Thailand, recently dismissed previous reports of the sale of Tesco UK's Thai assets.
It had never revealed to the media whether it would sell assets or not, according to the company statement. "The report has shaken global staff's confidence in theei employer," said the statement.
Tesco has an adjusted net debt of £6.6 billion (B330 billion), which is now 3.2 times its operating cash flow, and a huge pension deficit of £3.2 billion (B160 billion).