Financial stocks as a group were strong again Thursday, and among the gainers was Pittsburgh bank PNC Financial Services ( PNC).

Shares of PNC added 1.7% after it set plans for a 25 million-share repurchase program to replace the prior one. Its stock traded up $1.16 to $71.05 in support of both the NYSE Financial Sector Index and the KBW Bank Index, which were booking gains of 0.6% and 0.5%, respectively.

Also among the many other climbing financial stocks, with gains of 2.9% or more, were insurance broker Amtrust Financial Services ( AFSI), credit-card issuer MasterCard ( MA) and online broker Knight Capital ( NITE).

Jefferies, meanwhile, ratcheted up NYSE Euronext's ( NYX) third-quarter earnings estimate by 9 cents to 70 cents a share. The analyst cited Wednesday's trading volume report for September, which he said exceeded his expectations. Shares wavered in and out of the green, but were lately losing a penny at $81.46.

Merrill Lynch ( MER) ranked among the losers after The Wall Street Journal reported that it could see more than $4 billion in losses from subprime-mortgage exposure, possibly resulting in the greatest third-quarter profit hit of any U.S. securities firm.

Merrill has begun ousting the executives responsible, according to reports. These include former co-head of institutional securities Dow Kim, as well as Osman Semerci and Dale Lattanzio. Merrill shares were losing $1.58, or 2.1%, to $74.42.

Elsewhere, health insurer and managed-care provider Molina Healthcare ( MOH) lost 3.9% to $34.77 after the Long Beach, Calif., company offered $150 million in convertible senior bonds.

Among other sector losers, mortgage lender IndyMac Bancorp ( IMB) fell 4.7% to $23.10. BankUnited Financial ( BKUNA) was off 7% to $14.50, and Moody's ( MCO), a credit-ratings firm, slipped $1.67, or 3.1%, to $52.25.