* Client trades/day averaged 330,000 in Oct, near forecasts
* Brokerage-related assets up 10 pct versus a year ago
* Fee-based balances up 26 pct from a year earlier
NEW YORK, Nov 8 (Reuters) - TD Ameritrade Holding Corp , the No. 1 U.S. discount brokerage by trading volume, said on Thursday its average client trades per day fell 19 percent in October from a year earlier, highlighting the ongoing uncertainty that retail investors feel over the economy.
The trading environment is not likely to improve much until early next year, once issues like the so-called fiscal cliff are dealt with, TD Ameritrade Chief Executive Fred Tomczyk said in an interview on Monday.
The fiscal cliff is a $600 billion package of tax increases and spending cuts that will kick in at the end of the year, threatening U.S. economic growth, unless Congress agrees on a solution.
Clients of Omaha-based TD Ameritrade made an average of 330,000 trades per day in October. The month had two less trading days than October 2011 as U.S. equity markets closed due to Superstorm Sandy, the worst storm to hit the U.S. Northeast in 75 years.
Trading activity on a month-over-month basis was down 7 percent, which was "a bit better than management's mid-month update of down 8 percent, suggesting a slight uptick in activity recently," JMP Securities analyst David Trone said in a note to clients.
The level was slightly below Trone's forecast of a 6 percent decline, but above the 8 percent to 10 percent drop expected by BMO Capital Markets analyst David Chiaverini.
Total client assets were up 16 percent from a year earlier, but down 1 percent from September, at $469.9 billion. The S&P 500 was down 2 percent month-over-month.
Average client and brokerage-related assets were up 10 percent from a year earlier and 1 percent from September at $77.7 billion.
Average fee-based balances, invested in areas such as money-market funds and mutual funds, rose 26 percent from a year earlier and 1 percent from September to $98.1 billion.
Shares of TD Ameritrade were up 0.8 percent at $15.88 in midday trade on Thursday.