Friday may have brought more than 1 million trades to TD Ameritrade, but that record trading day didn’t show up in the Omaha company’s stock.

Rather, Ameritrade’s stock price has dropped by 14.2 percent since Thursday, before the vote calling for Great Britain to leave the European Union, a step known as Brexit.

The price drop most likely was due to uncertainty about the economic impact of the British vote plus the apparent indefinite postponement of any increase in U.S. interest rates, also tied to Brexit-related uncertainty, observers said Monday.

The vote in Britain adds enough economic uncertainty that interest rate increases by the Federal Reserve — thought before the vote to be probable — are now unlikely anytime soon, said Clint Rushing, a vice president of Smith Hayes Wealth Management in Omaha.

Rushing said investors know that continued low interest rates mean narrower margins and lower profits for banks and many other financial companies.

The Federal Reserve dropped interest rates sharply after the 2008-09 financial crisis to stimulate the economy with cheap credit. Now that the economy has recovered, modestly, businesses and investors are prepared for rates to rise to more normal levels.

But the uncertainty from Brexit has put such increases on hold, and at the same time may cause mom-and-pop investors to sell off holdings and revert to cash until the stock market settles down.

That would cut into Ameritrade’s revenue after the burst of trading on Friday and Monday.

“Sometimes these types of investors tend to second-guess their own strategy, and the market for them might dry up a bit,” said John “Buzz” Garlock, senior vice president at RBC Wealth Management in Omaha.

Despite collecting millions in fees from the high trading volume the past two days, the uncertainty stemming from the vote isn’t good for online brokerages, he said.

Ameritrade’s stock price dropped to $26.68 per share at the end of trading Monday from $31.11 on Thursday.

Other online brokerages saw even bigger declines: Charles Schwab Corp., down 19 percent to $24.05 per share, and E-Trade Financial Corp., down 16.6 percent to $21.83 per share.

The overall market declined, too, but not as much.

Since Thursday the Dow Jones industrial average is down 5.3 percent and the Standard & Poor’s index of 500 stocks is down 5.1 percent.

TD Ameritrade said in a statement that it fielded more than 1 million trades on Friday as U.S. investors awoke to learn about the British vote.

“These heavy volumes across the industry briefly caused some TD Ameritrade clients intermittent messaging and log-in delays,” the company said, adding that the surprise vote caught a market that had seen prices rising in recent weeks.

Market volatility could continue “over the next few weeks until things settle down a bit,” Ameritrade said, but uncertainty in Europe “will likely continue for quite some time.”

About 40 percent of Ameritrade’s revenue is from trading fees and commissions, with most of the rest from interest income and deposit fees.

In a report Monday, Credit Suisse analysts said Ameritrade and E-Trade have “modest ‘Brexit risk’ ” and their stock price declines seem “overdone,” making them “attractive” investments.

The report said Ameritrade, E-Trade and Schwab are “beaten-down stocks with resilient business models and U.S.-based franchises.”