Commercial banks with significant mortgage-servicing businesses saw much improved revenue and stronger asset valuations on these activities during the fourth quarter of 2005. Rising interest rates slowed prepayment speeds and allowed banks to recover hefty impairment reserves they stowed away in previous periods. Net income from servicing loans for other investors among the 40 largest bank mortgage servicers surged from $3.85 billion in the third quarter of 2005 to $5.32 billion in the final… [One data table included]