OMAHA, Neb. - Online brokerage TD Ameritrade Holding Corp. said Tuesday its third-quarter net income fell nearly 17 percent as low interest rates continued to restrict its revenue, but the results exceeded Wall Street expectations.

TD Ameritrade said the low interest-rate environment reduced the amount of interest revenue the company collects even though trading figures remained strong.

The Omaha-based company said it generated $170.5 million in net income, or 30 cents per share, in the quarter that ended June 30. A year ago, Ameritrade reported $204.4 million in net income, or 34 cents per share.

Without unusual items, TD Ameritrade would have earned 33 cents per share. The company said the unusual items included a special regulatory assessment paid to the FDIC, a payment on its past acquisition of Options 360 and a write-off of some software-development costs. Options 360 is a trading tool that helps investors research and analyze potential trades and manage options positions.

Analysts surveyed by Thomson Reuters expected TD Ameritrade to report earnings per share of 29 cents on $580.5 million in revenue.

TD Ameritrade shares gained 90 cents, or 5.1 percent, to sell for $18.62 in afternoon trading on Tuesday.

TD Ameritrade CEO Fred Tomczyk said he thinks the results show the company's strategy is working even in this challenging environment. Company officials have emphasized that they want TD Ameritrade to be ready to excel when markets improve.

"We are positioned to come out of the cycle an even stronger company with an improved competitive position, something we have been and continue to focus on as a management team," Tomczyk said.

FBR Capital Markets analyst Matt Snowling said the results show TD Ameritrade is executing on its strategy well. But he said in a research note that the company's earnings may decline in future quarters because trading typically slows in late summer.

Ameritrade said it generated $613.8 million revenue in the third quarter. That's down about 2 percent from $623.6 million last year.

Ameritrade says it handled an average of 391,506 trades per day in the quarter, up from 287,349 trades per day a year ago. That drove transaction-based revenue up 36 percent to $338.5 million in the third quarter.

But the Federal Reserve's interest-rate cuts drove a 28 percent drop in TD Ameritrade's asset-based revenue, which fell to $262.8 million.

TD Ameritrade also completed its $606 million acquisition of options-trading specialist thinkorswim during the quarter.

Credit Suisse analyst Howard Chen said in a research note that TD Ameritrade posted a solid quarter highlighted by strong engagement from retail traders.