The Company ended the quarter with $201 billion in total customer assets, compared with $204 billion at the end of the third quarter and $172 billion at the end of 2011.
During the quarter, customers added $2.3 billion in net new brokerage assets, totaling $10.4 billion for the full year. Brokerage related cash increased by $1.3 billion to $33.9 billion during the period, while customers were net buyers of approximately $0.5 billion of securities. Margin receivables averaged $5.8 billion in the quarter, up four percent sequentially and up 18 percent year over year.
Net operating interest income for the fourth quarter was $260 million, down from $261 million in the prior quarter and $289 million a year ago. Fourth quarter results reflected a net interest spread of 2.38 percent on average interest-earning assets of $42.9 billion, compared with a net interest spread of 2.28 percent on average interest-earning assets of $44.9 billion in the prior quarter.
Commissions, fees and service charges, principal transactions, and other revenue in the fourth quarter were $151 million, compared with $153 million in the prior quarter and $156 million in the fourth quarter of 2011. Average commission per trade for the quarter was $11.10, compared to $11.24 in the prior quarter, and $10.80 in the fourth quarter of 2011.Total operating expenses for the quarter decreased $4 million sequentially to $285 million. For the year, operating expenses were $1.2 billion. In December, the Company completed a refinance of its 12.50% Springing Lien Notes due 2017 and its 7.875% Senior Notes due 2015, using the net proceeds from a $1.305 billion issuance of new Senior Notes. The new Senior Notes were issued in two tranches - $505 million of 6.0% notes due 2017, and $800 million of 6.375% notes due 2019. The transaction, which resulted in a pre-tax loss of $257 million on early extinguishment of debt, lowered the Company’s annual debt servicing costs by approximately $70 million on a pre-tax basis.