The UK financial watchdog has launched a formal investigation into "accounting irregularities" at software firm iSoft.
MPs have also demanded an investigation into the firm
The probe by the Financial Services Authority (FSA) is believed to centre on whether the troubled firm misled investors over how much it had earned.
In recent weeks, iSoft has confirmed it found evidence of irregularities affecting its 2004 and 2005 accounts.
ISoft said the problems mainly related to the firm's revenues being stated earlier than they should have been.
A previous independent probe into iSoft's accounting problems also concluded there were grounds for a more formal investigation, iSoft added.
On Wednesday, growing concern about the health of iSoft prompted MPs to demand that the Department of Trade and Industry also investigate the company.
String of problems
The inquiry is the latest in a long line of problems to hit the group in recent months.
ISoft has twice delayed its annual results, once because of a change to accounting rules and a second time as reports of its accounting errors emerged. Reports suggest its results could finally be published this week.
The investigation into iSoft's accounts has also led to commercial director Steve Graham being suspended and another employee put on a special leave of absence.
In June, iSoft's chief executive Tim Whiston resigned.
Earlier this year, the group was also blamed for delays to a £2bn upgrade of the NHS computer system.