Interactive Brokers Profits When Trading Is Hot. What Happens When It Cools?

Bull markets affect not only stock prices but also some underlying businesses in the economy. For instance, trading brokerages -- like Interactive Brokers (NASDAQ: IBKR) -- earn more revenue if more people around the globe trade their equities.

The bull market that began in late 2022 helped Interactive Brokers' stock generate a total return of over 525% in the last five years. That performance is actually crushing the performance of most technology and artificial intelligence (AI) stocks over the same time period.

But what happens when trading eventually slows? Let's discuss the dynamics of the financial brokerage sector and what it could mean for Interactive Brokers investors today.

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Revenue is built on trading volumes

Interactive Brokers (IBKR) is a global financial asset trading platform. It makes money whenever a customer trades a stock, options, cryptocurrencies, or other financial assets. The more customers it has and the more trades each customer makes, the more money it will make.

The AI-driven bull market has been quite kind to IBKR's growth. Its total customers grew 34% year over year last quarter to 5.19 million, resulting in 30% growth in commission revenue. It also generates net interest income on cash balances and margin loans, which were up 23% year over year.

Profitability is also stellar, with a pretax profit margin of 77% last quarter. IBKR's stock price is up 506% in the last five years due to this stellar profit margin and the fact that it has been able to grow its customer accounts by 5x from around 1 million in 2020. This was helped by its improved product offering for international trading, as well as by the bull market during the pandemic and in the last few years around AI.

Cyclicality is the price of doing business

A market-share-gaining stock brokerage like IBKR is likely to deliver fantastic financial performance in a bull market. Bear markets are not so kind. Sure, trading is still going on, but when stock prices fall, it generally means some individual traders exit the market, and trading volume falls. This turns a previous tailwind into a headwind for as long as stocks remain in the doldrums.

This is the business cycle for IBKR, and a bear market will eventually arrive. In 2022, when stocks were in a bear market amid interest rate hikes and recession fears, IBKR's customer account balance was nearly flat, underscoring how macroeconomic forces can affect its business. Still, the fact that it was able to stabilize its business during a bear market is a testament to its market share gains.

Data by YCharts. PE = price-to-earnings.

Should you buy IBKR stock?

When evaluating brokerage stocks, one also needs to factor in interest rates and how they can affect cash being kept in brokerage accounts. How rates average out through both types of markets will help determine a brokerage's true long-term earnings.

For instance, more assets on the platform at IBKR have meant a growth in net interest income. And yet, this net interest income is currently growing more slowly than the overall customer count. This is because interest rates are down globally in the last year, meaning IBKR doesn't earn as much in interest income on idle cash balances. In a bear market, interest rates are likely to fall, which could affect the business's earnings growth.

Another factor to consider is stock valuation. IBKR stock currently trades at a price-to-earnings ratio (P/E) of 38.5, and this is valuing it on trailing earnings in a multi-year bull market. If a bear market occurs and lasts for years, IBKR's customers, net interest income, and likely overall earnings may fall temporarily. This could make it a dangerous investment to buy at a P/E ratio close to 40.

That's why it's important to make any decision on IBKR stock with a long-term investment view. IBKR should continue gaining market share over the long term, which is why the stock trades at such a premium earnings multiple today. I don't think it is smart to buy into the stock at this premium P/E ratio, but investors should keep it on the watch list to see if it ever gets cheap again. That's when a long-term investment might make sense.

Brett Schafer has positions in Interactive Brokers Group. The Motley Fool has positions in and recommends Interactive Brokers Group. The Motley Fool recommends the following options: long January 2027 $43.75 calls on Interactive Brokers Group and short January 2027 $46.25 calls on Interactive Brokers Group. The Motley Fool has a disclosure policy.