* 2.3 pct of Saipem placed at 30.65 euros - traders
* Saipem shares fell sharply after profit warning
By Stephen Jewkes and Giancarlo Navach
MILAN, Feb 4 (Reuters) - Italy's financial regulator has asked its British counterpart to probe a sale of shares in Europe's biggest oil services company Saipem before it warned profit would fall, a source close to the Italian watchdog said late on Monday.
The probe is the latest headache for Chief Executive Umberto Vergine who took the helm in December after his predecessor was forced out by an Italian investigation into alleged corruption in Algeria.
The Consob source said the watchdog suspects shares were sold in London and has called in the Financial Services Authority (FSA) to look into the timing of the sale and who sold shares to whom.
Saipem shares plunged by one third after the profit warning rattled investors last week.
"Consob has asked the FSA to look into the placement by Merrill Lynch to better understand what exactly went on," the source said, refering to press reports that Bank of America-Merrill Lynch had handled the sale.
Traders said Bofa Merrill Lynch was acting as a broker on behalf of a third party.
Bofa Merrill Lynch declined to comment. Consob, Saipem and the FSA also declined to comment
Last week, traders told Reuters that Bofa Merrill Lynch had on Jan. 28 started the process to sell 2.3 percent of Saipem shares on the market at 30.65 euros per share.
After the market closed on Jan. 29, Saipem warned net profit would be halved this year to 450 million euros.
Its shares tumbled 34 percent to 19.97 euros the following day, as investors questioned how a company operating in a sector buoyed by high oil prices and strong demand for rigs and other drilling engineering services could have got things so wrong.
In an interview with an Italian newspaper on Sunday, CEO Vergine said he had not been pre-alerted as to any placement and had learned of it from news agencies.
Vergine, a former manager at oil major Eni which owns around 43 percent of Saipem, and Chief Financial Officer Stefano Goberti met Consob on Monday for more than two hours. The two managers left without comment.
At 1251 GMT on Tuesday, Saipem shares were up 1.2 percent at 20.45 euros.