SYDNEY, May 19 (Reuters) - Macquarie Group (MQG)...

SYDNEY, May 19 (Reuters) - Macquarie Group (MQG) inappropriately disclosed confidential information about its trading activities and clients, Australia's corporate watchdog said on Friday as part of an investigation into the country's biggest banks.

The Australian Securities & Investment Commission (ASIC) said Macquarie's banking arm failed to prevent the disclosure of confidential information to third parties and other "inappropriate conduct" from 2008-2013.

"Macquarie acknowledges ASIC's concerns relating to certain aspects of its wholesale spot FX business," Macquarie said in a statement on its website.

"Macquarie has commenced a programme of work to address these concerns, which will be reviewed and assessed by an ASIC-appointed independent consultant."

ASIC has found a series of violations in the banking industry, as part of its investigations into Commonwealth Bank (CBA), Westpac (WBC), ANZ Banking (ANZ) and National Australia Bank (NAB).

Australia's four major lenders have come under fire following several scams including misleading financial advice, insurance fraud and interest-rate rigging, as well as for refusing to pass on official interest rate cuts in full.

The four together control 80 percent of Australia's lending market and are extremely profitable.

Following ASIC's findings into the banks' wholesale forex businesses, the "Big Four" agreed to make voluntary contributions of a total A$11 million ($8.2 million) to fund independent financial literacy projects in Australia.

Macquarie will make a voluntary contribution of A$2 million. In a separate statement on Friday, ASIC said Australia's "Big Four" banks and AMP (AMP), have so far repaid A$60 million in refunds and interest for failing to provide financial advice to customers while charging them ongoing advice fees.

These institutions' total compensation estimates for advice delivery failures stand at more than A$204 million, plus interest, ASIC added.

($1 = 1.3452 Australian dollars)