TD Ameritrade's (AMTD) fiscal first-quarter profit climbed 65%, with client-trading volumes jumping as the markets took a wild ride.The online broker said Thursday that its profit for the December period rose to $240.8 million, or 40 cents a share, from $145.6 million, or 24 cents a share, a year earlier. Analysts, on average, expected earnings per share of 39 cents, according to Thomson Financial. TD Ameritrade's net revenue grew to $641.6 million from $545.2 million, exceeding Wall Street's $623.7 million forecast. The gains came amid a rocky period in the markets, brought on by turmoil in the mortgage industry, that likely helped spur client trading. As well, E*Trade Financial ( ETFC) suffered a near meltdown from its own mortgage-related bets during the quarter, benefitting rivals like TD Ameritrade and Charles Schwab ( SCHW). TD Ameritrade said it had record average client trades per day of 322,000, up 35% from a year ago. Its investable asset balances increased 10% to $31 billion. For fiscal 2008, TD Ameritrade now expects earnings of $1.23 to $1.41 a share, suggesting a midpoint of $1.32. In September, the company projected earnings around $1.27 a share. Analysts anticipate earnings of $1.36 a share for the year ending in September.