Banks and other companies that have seen borrowing costs rise in the past year are about to feel more pressure in a $1 trillion market for short-term IOUs.

Investors are poised to pull as much as $400 billion from U.S. money-market funds that buy such debt, known as commercial paper, JPMorgan Chase & Co. predicts. The looming exodus, a consequence of steps to make money markets safer after the financial crisis, is set to accelerate before October. That’s when Securities and Exchange Commission rules take effect mandating that so-called institutional prime funds, among the main buyers of commercial paper, report prices that fluctuate. Traditionally, those funds have stuck to $1 per share.

Wall Street strategists say investors may already be shifting from prime funds to those focused on government debt, which will keep a fixed share price. The diminished appetite for commercial paper is a potential headache for banks and other issuers, which saw the cost of the IOUs climb to an almost four-year high in recent weeks. The companies use the instruments for everything from loans to payrolls.

Commercial-paper “issuers will either have to find other investors to fill in the gap, or may have to raise the rate they are offering to get additional interest,” said  Gregory Fayvilevich, an analyst in the fund and asset management group at Fitch Ratings in New York.

Next Wave

The move by investors is the next big wave of cash to leave prime funds because of the new rules. It would come on top of about $250 billion of assets that U.S. money-fund companies have already converted over the last year from prime funds to those that only hold government securities like Treasury bills. The SEC measures will force institutional prime funds to tell clients daily whether their investments gained or lost value.

The money-market industry’s changing landscape has already lifted companies’ short-term borrowing costs: Rates on six-month commercial paper reached the highest above Treasury bills since 2012 this year as demand waned relative to government debt.

Financial firms’ short-term debts, including commercial paper, certificates of deposit and time deposits, make up U.S. prime funds’ biggest holdings. Bank of Tokyo-Mitsubishi UFJ Ltd., Credit Agricole SA, Sumitomo Mitsui Bank Corp., Royal Bank of Canada and DNB Bank ASA comprise the top five issuers of this debt held by the funds, according to Crane Data LLC.

Longer maturities and more diversification are part of the answer at Credit Agricole CIB, said Oskar Rogg, head of Treasury for the Americas in New York. “We certainly do have a lot with prime funds. But in terms of our relative dependence on that for funding our core assets,” it isn’t high.

Diversified Approach