TD Ameritrade Corp. (NASDAQ: AMTD) saw a Q1 net income growth to the tune of 65% [subscription required] as more of its retail customers placed trades in the turbulent market during the final quarter of 2007. That's not all, though: the company said 2008 earnings would be better than its previous outlook.

In perfect market fashion, the company's shares rose slightly and then tanked over 4%. AMTD shares stand at $18.08 as of 12:27 p.m., down 4.79% from yesterday's close. This, after the company reported a 65% net income rise in its Q1's fiscal period, with $240.8 million in net income or $0.40 per share and shares indicated up over 4% in premarket trading.

For the trading company's Q1 period, it reported an average of 321,736 client trades per day -- up 35% from the year-ago quarterly period. Seeing as though the final three months of 2007 saw some wild swings in tech stocks (among other sectors), TD Ameritrade's customers were on an apparent trading frenzy of sorts.

However, the company reported that client assets fell 0.8% to $300.4 billion for the quarter ended December 31st. The total includes $47 billion in cash and money market funds within all consumer client accounts. All those consumer trades, all those assets, and a brighter 2008 outlook -- and AMTD shares go down as a result. You have to love the market's interpretation of good results.