Thailand mobile operators Advanced Info Service and True Corp. won 4G mobile spectrum in an auction of 1.8 GHz spectrum. The licenses run for 18 years.

Market leader AIS, 23 percent owned by Singapore Telecommunications Ltd, had been the only major Thai mobile service provider that did not offer 4G services.

True Corp is 18 percent owned by China Mobile.

As often is the case, there is a “winner’s curse.” Because prices paid at auction were high, AIS and True will face financial pressure in the form of balance sheets that are more challenged, some note.

“The spectrum auctions are shaping up to be far more expensive than what we or the street had initially envisioned given the participation of Jasmine International,” Arthur Pineda, analyst at Citigroup said in a note.

Ratings agency Fitch warns that prices paid in the recent 1.8 GHz spectrum auction were significantly higher than Fitch’s expectations.