(AMTD) - Get Report

was skidding for a second straight day after the online brokerage said third-quarter earnings were trending toward the low end of its previous guidance.

Ameritrade, which reported a sharp drop in June trading activity, put third-quarter earnings closer to 14 cents a share than 22 cents a share in a press release. Analysts had been forecasting earnings of 17 cents a share in the quarter, which ends June 30.

Ameritrade said its customers averaged a total of 144,000 trades a day last month, down from an average of 200,000 trades in April. The company opened 25,000 new accounts and closed 10,000 in May, leaving a total of about 3.48 million accounts at month's end, up from 3.46 million a month earlier.

The stock was recently down 49 cents, or 4.2%, to $11.22 on the Instinet premarket session. CSFB lowered its 2004 earnings estimate for the company to 62 cents from 68 cents, and cut its price target for the stock by $3 to $16. The brokerage blamed low-volume equity markets for Ameritrade's woes.

Thursday's slide would follow a near 7% drop for Ameritrade Wednesday after the company's CEO talked down full-year earnings estimates of 79 cents a share. Since peaking above $17 in early March, the stock has lost about 35% of its value.

Ameritrade's average client margin balances in May were approximately $3.6 billion. On May 28, 2004, client margin balances totaled approximately $3.3 billion. Client assets totaled approximately $71.2 billion, of which cash and money market assets totaled $12.6 billion.