
STEC shares dropped to Bt4.50 yesterday after gaining on Wednesday when it closed at Bt4.76, up 8.68 per cent from Tuesday's close of Bt4.38.
STEC was founded by Chaovarat Chanweerakul, the interior minister and leader of the Bhumi Jai Thai Party, a powerful partner in Abhisit Vejjajiva's coalition government.
Chaisit Kururat, chairman of the bidding committee, said STEC proposed the lowest price for construction of the 11-kilometre western extension of the Skytrain system.
The contract covers eight stations, starting at the Rama III Bridge and ending at Klong Bang Pai on the Thon Buri side of Bangkok, as well the structure across the Chao Phya River.
CKTC Joint Venture, led by Ch Karnchang, another local construction giant, proposed Bt15.6 billion for the contract, while ITON Joint Venture, led by Italian-Thai Development, offered Bt16.35 billion.
CKTC has already won the first 12-kilometre section of the Purple Line, a long-delayed mega-infrastructure project.
The Mass Rapid Transit Authority (MRTA) will shortly finalise the price for the second contract before seeking Cabinet approval to sign it.
The Purple Line project will be financed partly by loans from the Japan International Cooperation Agency.
MRTA deputy governor Chukiat Photayanuwatr has negotiated with CKTC to lower the first contract from Bt16.7 billion to Bt14.9 billion.
The first contract covers the eastern section of the Purple Line, running from the Taopoon area to the Rama III Bridge.
The government has capped the Purple Line's overall budget at Bt36 billion, including the third contract for a sub-depot and other works.
Originally, the budget was set at Bt31 billion, but then oil prices soared to a record US$147 a barrel at the time of the bidding invitations last year, prompting the government to raise the budget to Bt36 billion.
Crude oil prices have fallen to about $70 (Bt2,400) per barrel at present.
The State Railway of Thailand has already awarded the job to build the Taling Chan-Bang Sue section of the Red Line. Work is now underway to relocate squatters from the construction site.