BOSTON ( TheStreet) -- Goldman Sachs ( GS) retraced early losses and was among the winners of the financial sector late in Monday's session despite an audit threat from regulators over derivatives trades.

Goldman Sachs initially traded lower after a report the bank is facing a threat by the Financial Crisis Inquiry Commission to bring in outside accountants to examine the bank's systems for data on its derivatives business.

The threat comes after Goldman's executives maintained they do not track trading revenue generated strictly from derivatives, the Financial Times reports. "We have a deep level of questioning about whether we're getting the straight scoop here and whether Goldman is working with us on information that they surely have," FCIC Chairman Phil Angelides told the paper.

After trading as low as $145.21 earlier in the day, Goldman Sachs shares were lately up 12 cents, or 0.1%, to $147.50.

In other bank news, Citigroup ( C) has found a security flaw in one of its key mobile banking apps designed for Apple's ( AAPL) iPhone, TheStreet's James Rogers reports, but the bank denied there's any data breach.

"During a recent review, we discovered that our U.S. Citi Mobile iPhone banking app was accidentally saving information related to customer accounts in a hidden file on their iPhones," explained a Citi spokeswoman in an email to TheStreet. "There has been no data breach," she added.

Citigroup shares were up 11 cents, or 2.7%, to $4.13.

Among other U.S. bank stocks trading higher, Bank of America ( BAC) gained 2.8% to $14.13, Wells Fargo ( WFC) was higher by 1.3% to $27.78, JPMorgan Chase ( JPM) rose 0.6% to $40.08, and Morgan Stanley ( MS) tacked on 0.5% to $27.01.

Other winners included Synovus Financial ( SNV), which rebounded from losses Friday after the company reported a second-quarter loss of 36 cents a share, compared to the Thomson Reuters estimate for a loss of only 6 cents a share.

On Friday, FBR Capital Markets analyst Paul Miller reiterated his "market perform" rating on Synovus shares but lowered his price target to $2.50 from $3, noting that "credit trends were mixed and Synovus delayed expectations of profitability due to macroeconomic factors."

During Monday's session, Synovus shares were jumping by 8.2% to $2.57.

Overseas banks were also performing strong in the wake of the stress tests on EU banks. Among them, Bank of Ireland ( IRE) rallied 11% to $4.53, Barclays ( BCS) was higher by 4.7% to $19.77, Allied Irish Banks ( AIB) climbed 3.5% to $2.64, Lloyds Banking Group ( LYG) advanced 3.3% to $4.08, and National Bank of Greece ( NBG) was up 2.9% to $2.88.

-- Written by Robert Holmes in Boston.

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