TD Waterhouse ( TWE), a leading discount and online brokerage firm, reported Wednesday that its net income rose 156%, easily beating analysts' expectations, but volatility in the market through April kept traders on the sidelines and tripped the brokerage's momentum.

Some analysts are pointing to a seasonal slowdown as summer approaches and a lack of enthusiasm among investors after the hasty retreat of the Nasdaq Composite Index since March.

Last week, David Pottruck, president and co-chief executive of Charles Schwab ( SCH), attributed a slowdown in his firm's trading activity to a "seasonal pattern."

While almost all other TD Waterhouse financial data was in excess of Wall Street estimates, a closer look at the revenue trades per day numbers in April showed a significantly slower rate of growth.

Revenue trades per day, or the amount of money the company takes in from fees on trades, increased 65% from January to March, but that number for the three months ended April grew at about half that rate, at 34%, as the total number of trades dropped sharply.

Net income rose to $76.6 million, or 20 cents a diluted share, in Waterhouse's second fiscal quarter, from $30 million, or 9 cents a share, a year earlier. The results represented a 34% gain over the first quarter of the year.

Analysts surveyed by First Call/Thomson Financial had been expecting earnings of 16 cents a share in the latest quarter.

Excluding the impact of goodwill, earnings per share were 23 cents in the second quarter, compared with 11 cents a share a year earlier and 17 cents a share in the first quarter.

Total revenue for the quarter jumped 96%, to $489 million, from $249 million in the year-earlier quarter.

Shares of New York-based TD Waterhouse rose 1/16, or 0.3%, to 18 3/4 in late-morning trading. (TD Waterhouse closed down 1/8, or 0.7%, at 18 9/16.)

"Our growth sets the stage for continued expansion in the second half of the year, with our investment in marketing and technology keeping pace with revenue gains," Stephen McDonald, chief executive, said in a statement. "We will continue to focus on our growth strategies, and remain on track to exceed our aggressive targets for fiscal 2000: 1 million new customers (exclusive of acquisitions), a $60 billion increase in customer assets and improved operating margins."

Shares in its parent company, Canada's Toronto-Dominion Bank ( TD - Get Report), were down 3/16, or 0.8%, to 24 9/16 in late-morning trading on the New York Stock Exchange. (Toronto-Dominion Bank closed up 3/16, or 8%, at 24 15/16.)