By Karen Brettell
NEW YORK, June 29 (Reuters) - The borrowed money helping to fuel the U.S. stock rally is getting more expensive, and some on Wall Street are starting to wonder how much longer the math will work.
Inflows into leveraged exchange-traded products, rising stock options trading volumes and record hedge-fund exposure are collectively straining the global balance-sheet capacity of the large banks that offer equity financing, driving up the costs of the loans that underlie much stock trading.
Primary dealers — banks that trade directly with the Federal Reserve and facilitate markets across the financial world — are carrying record equity repo exposure, surpassing $220 billion. Repo is short for the repurchase agreements in which traders borrow from banks for terms as short as a day in exchange for securities, then repurchase the securities when the loan expires.
Some market measures that track the spread between implied financing rates for S&P 500 total-return futures and benchmark rates such as SOFR — the rate banks use to lend to one another on collateral overnight — show costs at a record in data going back to late 2020, excluding year-end periods that are often characterized by funding squeezes as banks and others gussy up their portfolios for reporting purposes.
Though rising repo costs are just a cost of doing business when markets are rising, when stock prices flatline or fall the calculus can change and accelerate traders' retreat from markets.
”Equity funding is the canary in the coal mine for a reset of investor perception about financial conditions," said Martin Tobias, a strategist at Morgan Stanley. He said the risk is that high costs could make some trades using borrowed money too expensive to attempt, further narrowing markets.
SURGING DEMAND DRIVES FINANCING COSTS
Stocks have rallied in 2026, pushing the Nasdaq Composite Index to 20 record closes this year, as AI spending on chips and other goods drives surging profit growth while investors remain confident the U.S. economy can avoid a recession.
Stefano Pascale, head of U.S. equity derivatives strategy at Barclays, said higher financing costs reflect growing demand to participate in the market — a sign of confidence more than a cause for concern.
"The cost of financing going higher typically coincides a little bit with periods of euphoria," he said. "The cost of financing going higher is not, per se, a problem for the market."
The consequence, he added, falls mainly on trades that rely heavily on cheap financing, where rising financing costs may force some leveraged investors to pull back.
The euphoria is visible in flows. Assets in U.S.-domiciled leveraged exchange-traded products doubled in the last few months to around $200 billion, driven by technology and semiconductor-linked products.
Options demand has added another layer. Investors who had cut risk during the recent Iran war rushed to buy upside exposure after a ceasefire, driving a surge in call-option activity that further strained dealer capacity.
Stock market gains themselves and rising equity issuance are also tightening capacity. Barclays estimates that if the equity financing market is around $10 trillion, then a 10% rise in equities can create roughly $1 trillion of additional financing demand, potentially adding $150 billion to $200 billion of risk-weighted assets — the capital banks must hold against those positions — for the banks that intermediate those trades.
BROADER FUNDING REMAINS ACCOMMODATIVE
The Treasury repo market has remained accommodative even as equity financing costs rise.
Samuel Earl, a U.S. rates strategist at Barclays, said changes this year to the Supplementary Leverage Ratio — a rule governing how much capital large banks must hold relative to their total assets — gave large U.S. banks more room to handle government bond trades. But equity financing is more capital-intensive, consumes more liquidity under bank rules, has stricter counterparty limits and lacks the central-clearing release valve that helps dealers net Treasury repo positions, he said.
Whether strong stock valuations can continue has consequences beyond markets.
Andy Constan, founder and chief investment officer at Damped Spring Advisors, said rising asset prices have become a critical support for U.S. consumption at a time when real wage growth is weak. "If the stock market just stays where it is, that influence disappears," he said.
LEVERAGE FOCUSED ON SEMICONDUCTORS
For Morgan Stanley, the risk lies not just in growing dependence on leverage that is becoming more scarce, but in the concentration of stocks underpinning the rally.
Indeed, only one of the 11 S&P 500 sectors has outperformed the broader index over the past three months: Information Technology, home to chip firms such as Nvidia, Broadcom and recent favorite Micron, whose shares have more than tripled this year. Within that sector, semiconductors and semiconductor equipment account for roughly half the weight.
Morgan Stanley's Tobias said that peaks in stocks have coincided with highs in equity financing costs. With funding pressures rising into quarter-end and the S&P 500 struggling to break over its 7,621 high on June 2, the market could be facing an inflection point.
“What's propelling the market higher isn't a broader reflection of the outlook for the U.S. economy. It's simply leverage that's being concentrated in one very narrow part of the market,” said Tobias.
(Reporting by Karen Brettell in New York; Editing by Colin Barr and Matthew Lewis)
