* OFT fines six recruitment agencies 39.27 mln pounds
* Hays fined 30.4 mln stg, 50 pct of forecast FY net profit
* Hays CEO says fine disproportionate, considering appeal
* Unit of CDI Corp fined 7.6 mln stg
* Shares in Hays drop as much as 4 pct
(Adds comment from Hays, updates share price)
By Catherine Bosley
LONDON, Sept 30 (Reuters) - Britain's consumer watchdog has fined six recruitment agencies for price fixing and forming a cartel, slapping a penalty on market leader Hays Plc that equals half its estimated 2010 net profit.
The Office of Fair Trading (OFT) said on Wednesday that Hays, Britain's biggest recruitment firm, and five other agencies had boycotted ParcUK whose business as an intermediary between staffing agencies and construction companies threatened to erode the margins enjoyed by recruitment firms.
The OFT imposed fines totalling 39.27 million pounds ($62.61 million) on the six recruitment firms for breaching the Competition Act of 1998.
"Instead of competing with Parc -- and each other -- on price and quality, the parties formed a cartel," the OFT said, adding that group members, who met five times between 2004 and 2006, agreed to boycott Parc and fix rates they would charge to construction companies.
The highest fine of 30.4 million pounds was given to Hays, which is expected to post a net profit of 61.4 million pounds in the year to June 2010, according to the average of five analysts' forecasts on Reuters Estimates.
Alistair Cox, chief executive of Hays, said the company was considering an appeal.
"The level of the fine is wholly disproportionate with the activities to which it relates," he said in statement. "The OFT's investigation related to an isolated matter arising from the conduct of a single employee who is no longer with the company."
Meanwhile, CDI AndersElite, a unit of CDI Corp, was fined 7.6 million pounds, while private companies Eden Brown, Fusion People, A Warwick Associates Ltd, and Henry Recruitment also received penalties. AndersElite declined to comment.
Two other recruitment agencies involved were granted immunity from fines because they exposed the cartel, the OFT said, and most of those fined were given discounts for cooperation.
"This is a serious breach of competition law and the level of fines reflects this," Heather Clayton, the OFT's senior director, said in a statement.
"Ultimately it is the consumer and the wider economy that loses out from such behaviour."
Shares in Hays were down 3.5 percent at 104.8 pence by 1234 GMT. They have risen 50 percent so far this year, outperforming the FTSE support services index. (Reporting by Catherine Bosley; editing by Rupert Winchester)