The JWT network recently secured a 14-country ad contract for rival Vodaphone, and while Vodaphone is not active in the Thai market now, "we are unable to offer Orange any long-term contractual guarantees", said JWT chairman and chief executive officer Mark Webster.
"It is one of the unfortunate things about our industry and beyond both our control."
TA Orange, which stormed into the Thai market in March, spent 556 million baht in the first eight months of the year, according to Nielsen Media Research figures, and has confirmed its total marketing budget at 1.5 billion baht.
Orange communications affairs manager, Duke Theerathada, declined to name the four agencies that will pitch for the account.
However, industry sources have named them as Lowe, TBWA (Thailand), Prakit FCB and DY&R. The winning agency will take up where JWT leaves off. "The DNA will be the same, based around the Orange concept, but we'll have to develop next year's theme with the new agency, said Theerathada. A decision on the new agency is expected in November.