Datek Online Holdings

said its average trades and customer accounts swelled in the fourth quarter despite weak market conditions.

The privately-held online brokerage said the number of customer accounts more than doubled to 692,065 from 339,798 accounts at the end of 1999. Average online trades each day rose 31% to 106,143 from 81,005 in the same period last year.

However, customer assets, or the total assets held in accounts, were flat with the $10.8 billion recorded in the fourth quarter last year, and fell from the $14.8 billion recorded at the end of the latest third quarter.

Datek's announcement follows rival

Ameritrade's

TheStreet Recommends

(AMTD) - Get TD Ameritrade Holding Corporation Report

first-quarter

profit warning. Ameritrade said yesterday it would lay off 230 employees, or about 9% of its work force, as stock trading grew slower than expected in recent months.

Shares of Ameritrade recently dipped 39 cents, or 4.7%, to $8.19 in

Nasdaq

trading.