TD Ameritrade Holding Corp. said it earned $136.2 million, or 23 cents per share in its fiscal first quarter that ended Dec. 31, 2009, missing analysts’ consensus forecast by three cents a share, according to estimates culled by Thomson Reuters.

The Omaha-based discount brokerage and provider of custody services to registered investment advisers said trading volumes in the quarter decreased from recent record highs while revenue continued to be hurt by exceedingly low interest rates. But the company said it has been “encouraged” by the level of retail investor “engagement” thus far in January 2010.

The company’s gross new accounts in the quarter fell 17% from a year earlier to 180,000 even as net new client assets grew at an annualized rate of 12% over beginning assets to $87 billion. Average client trades per day rose 6% from a year earlier to 379,000.

TD Ameritrade said 45% of its $625 million of net revenue in the quarter was asset-based. Out of about $319 billion of client assets at the firm, a record $58 billion was being held in cash at the end of 2009, the company said.

“Despite the ongoing low interest rate environment, we have actually increased our asset-based revenues quarter-over-quarter, largely due to our strong organic growth and the implementation of our new cash management strategy,” said the company’s chief financial officer, Bill Gerber.

Like other discount brokers, TD Ameritrade has been sweeping cash balances from money-market accounts into bank accounts, offering for the time being slightly better rates to investors and gleaning more revenue for itself. The company also has been refinancing its debt “on attractive terms,” it said.

Unlike its competitor Charles Schwab Corp., which also is expected to report quarterly earnings today, TD Ameritrade does not break out data about trading volume and net new assets in its institutional, or custody, division that services registered investment advisers.

But TD Ameritrade said that average daily trades being made by clients in January rose to 408,000 from an average of 379,000 in the last three months of 2009.

Much of the rise in volume in the previous quarter and this month to date was driven by options trading related to TD Ameritrade’s purchase last year of thinkorswimgroup, Inc., company president and chief executive Fred Tomczyk said in a conference call with analysts Tuesday morning.