Fourth-quarter profit more than doubled at Charles Schwab ( SCHW), the nation's largest discount brokerage. The San Francisco-based broker earned $467 million, or 37 cents a share, compared to $187 million, or 14 cents a share, in the year ago period. The quarter included a $205 million non-cash tax benefit stemming from the sale of its U.S. Trust asset-management to Bank of America. Excluding the tax benefit, Schwab says it earned 21 cents a share on an operating basis. Revenue rose 15% to $1.62 billion. Analysts as surveyed by Thomson Financial were looking for earnings of 21 cents a share on revenue of $1.27 billion. Schwab reported earnings a day after TD Ameritrade ( AMTD), one of its main competitors in the online brokerage sector, also posted strong earnings.