(Bloomberg) -- Citigroup Inc. should have more than $500 million it says it mistakenly transferred to Revlon Inc. creditors returned, financial services trade groups told a federal judge ahead of a trial over the payments.

Citi says an employee’s error caused it to accidentally send more than $900 million in August to Revlon lenders who were expecting a periodic interest payment, some of whom were engaged in a dispute with the struggling cosmetics giant. While the bank has recovered about $390 million, it has sued more than a half-dozen firms that have refused to return the money. A trial is scheduled to begin next month before U.S. District Judge Jesse Furman in Manhattan.

On Wednesday, the trade groups filed briefs in the case in support of Citigroup, urging Furman to force firms that manage the loans for the creditors to return the funds. Those firms include Brigade Capital Management LP, HPS Investment Partners and Symphony Asset Management LLC.

The groups said a court ruling allowing the firms to keep the money would expose banks that facilitate wire transfers and serve as administrative agents to unnecessary risk.

‘Mistakes Do Happen’

One of the briefs was filed by the Loan Syndications and Trading Association, a not-for-profit group that represents more than 500 firms involved in the origination, syndication and trading of commercial loans whose members include both Citigroup and most of the creditors involved in the case. The group said that while the syndicated loan market is largely automated, “mistakes do happen” and participants routinely return incorrect payments, as have many of the Revlon creditors.

“We believe that regular participants in the syndicated loan market would be surprised and disappointed to find that the law entitles recipients to keep such payments,” the association said. “We are also firmly convinced that a ruling validating the retention of the payments in this case would undermine the smooth functioning of syndicated lending and the ability to transfer and assume loans under credit agreements by encouraging the kind of non-cooperative opportunistic behavior that destabilizes any market dependent on trust and transparency.”

Read More: Citigroup Gets Freeze on Brigade Money in $900 Million Error

The creditors have argued that they should be able to keep the money as “discharge for value” under a 1991 New York court ruling that says a creditor can keep money transferred in error under certain circumstances. They had opposed the groups’ attempt to file briefs in support of Citigroup, saying they had “serious concerns” about bias.

In another brief filed in support of Citigroup’s position, trade groups including the Bank Policy Institute argued that allowing the creditors to keep the funds would “impose overly broad and inequitable risks on banks that provide critically important wire transfer services to the public.”

“Doing so would undermine the critical role banks play in providing this essential, low-cost payment system to participants in the financial markets,” they said. “A ruling in defendants’ favor would markedly expand the application of the discharge for value defense, and the natural outcome of such a ruling would be a reduction in the number of banks willing to offer wire transfers and an increase in charges and costs to market participants.”

The case is Citibank NA v. Brigade Capital Management, 20-cv-6539, U.S. District Court, Southern District of New York (Manhattan).

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