NEW YORK, May 6 (Reuters) - The Treasury Borrowing Advisory Committee (TBAC) discussed on Tuesday a proposal for the U.S. Treasury to invest in the overnight repurchase or repo market, a potentially significant shift in cash management policy, according to minutes of that meeting that were released on Wednesday.

TBAC is a private-sector advisory group that counsels the U.S. Treasury Department on government financing, debt issuance strategy and overall market functioning.

The Treasury typically keeps its cash balance at the Federal Reserve, where it earns a minimal return, but is considered risk-free.

Tuesday's minutes debated whether the Treasury should lend its excess cash in the repo market "to generate investment returns while maintaining prudent risk management and avoiding market disruptions." The discussion reflects a growing focus on optimizing the Treasury's large and often volatile cash balance, particularly as borrowing needs remain elevated.

When the Treasury accumulates large balances at the Fed called the Treasury General Account (TGA), that cash is essentially withdrawn from the private financial system, draining reserves and tightening overall market conditions. This dynamic can contribute to volatility in short-term funding markets, particularly during periods of stress.

By being a lender in the repo market, the Treasury essentially recycles that cash back into the banking system. This then reduces pressure on repo markets during periods of elevated demand such as the end of the month or quarter.