Margin Bets Now Top $1 Trillion. Watch Out Below.

If you want to make a lot of money in the stock market, it helps to be acutely aware of current trends—and to constantly search for moments when they could shift into a hard turn.

We’re facing such a moment now.

Investors expect the Federal Reserve to lower interest rates this month, largely because that is what President Donald Trump wants.

Should the Fed not do so because inflation is difficult to forecast amid tariff diplomacy, the markets could react poorly. But if the Fed does lower rates, the cost of capital decreases, and that should position stocks and the economy for more growth.

Making things more interesting, there’s a sword of Damocles menacing Wall Street: a massive leveraged position financed with borrowed money that hangs over the stock and options markets.

Investors have borrowed more than $1 trillion to wager on markets. This is the first time margin loans have exceeded $1 trillion, which could become a shock wave if the central bank asserts its independence.

When institutional investors have high convictions, they often maximize position sizes to increase profits. The typical approach is to borrow money to increase their stake by an additional 17%— the so-called Kelly Criterion. Should something diminish their conviction—say, an unexpected turn of events—watch out.

For options investors, the heightened potential for volatility over the next few weeks is a reminder that it’s important to know when to be a wolf or a fox. When outcomes are unclear, a foxlike focus on risk rather than reward is prudent.

Risk management takes many forms.

Investors who regularly sell options with strikes near the stock price can reduce their position risk by focusing on call and put options that are 5% or even 10% away from the stock price. They should consider taking profits after a 50% gain, rather than the usual 80%.

The shift generates less money but also reduces the probability that the stock price violates the strike.

Individual investors with margin loans should reduce their leverage to shield unrealized gains and protect themselves should the Fed’s September meeting make this issue of market trends and turns quite real.

Until now, the market trend has been undeniable: Corporate earnings are growing, and stock prices have advanced to record valuations. But earnings season is largely over, and macroeconomic concerns will more heavily influence the market’s trajectory.

Trump’s insistence on lower interest rates clouds the moment. At best, the Fed faces mixed economic data, and at worst, a complicated political environment.

The president wants to control the central bank. Fed Chair Jerome Powell and the bank’s governors seem ill suited to prevail in a historic battle royale against a rough, tough president who has learned to use the political and bureaucratic systems as cudgels to achieve policy goals. Still, the Fed’s governors have the vote that sets rates.

Investors should recognize that there is little to be gained by trying to game the moment. Wait until the Fed concludes its monetary-policy meeting on Sept. 17 and it becomes clearer if the bullish trend continues, or if it turns and changes course. For this reason, we previously suggested investors should prepare for a stock market decline, or play the upside with call options.

How will investors on margin react to the Fed’s action or inaction? Do they rotate into investments with less risk than growth equities, or stay convicted on the trend?

Investor positioning data indicate a rise in defensive hedging ahead of the Fed’s decision. That activity is inconsequential when compared with the potential tsunami that could arise if investors are forced to sell stocks to satisfy their margin debts.

—

Originally Posted September 3, 2025 – Margin Bets Now Top $1 Trillion. Watch Out Below.