Persistent challenges such as margin compression and rising expenses will eventually force more banks to sell.

A breakdown of M&A announcements in the financial services industry for the week ended January 26.

Investar would acquire a bank with two branches in southeastern Louisiana.

Expenses weighed on UnionBanCal in San Francisco in the fourth quarter. Earnings at the $97 billion-asset company, which is wholly owned by Bank of Tokyo Mitsubishi UFJ Financial Group, fell 4.7% from a year earlier, to $123 million.

The Federal Deposit Insurance Corp. is seeking $29.9 million in damages in a lawsuit against 11 former officers and directors of failed First National Bank of Georgia.

JPMorgan Chase (JPM) is pushing back against a shareholder proposal to let investors vote on whether the bank should consider taking itself apart.

The Little Rock, Ark., bank plans more deals in addition to its agreement to buy First National Bank of Shelby in North Carolina. Similar deals by other buyers could be on the horizon.

The country's largest banks are counting on mobile technology to help them keep customers, win new business and — especially at Citigroup and Bank of America — replace branches.

Prosperity Bancshares (PB) in Houston ended a year in which it completed five deals and announced another with a jump in profit.

Sterling Financial (STSA) in Spokane, Wash., fell short of fourth-quarter earnings expectations because of a hefty charge for early repayment of debt.

Stimulus spending and Obamacare are making health care a viable way for banks to diversify their loan portfolios.

Iberiabank (IBKC) in Lafayette, La., reported a jump in fourth-quarter profit thanks to higher fee income and lower interest expenses.

Some banks have money to spend on deals. But many buyers are busy digesting past deals or wary about tight margins and the economy, executives said in fourth-quarter earnings calls.

Opus Bank in Irvine, Calif., has reshuffled its mix of branch office locations, as it enters Arizona and expands in the greater Los Angeles and Seattle areas.

Citigroup (C) is combining its leveraged finance origination and syndication businesses in the U.S., according to two people with knowledge of the matter.

Bank of the Ozarks in Little Rock, Ark., is raising its profile in North Carolina. The $4 billion-asset company announced Friday it is buying The First National Bank of Shelby in Shelby, N.C., for roughly $67.8 million in cash and stock.

Trustmark (TRMK) has received approval from regulators to buy BancTrust Financial Group in Mobile, Ala. The Jackson, Miss., company had waited months for approval to by BancTrust Financial Group (BTFG).

Citigroup has paused its sweeping cost-cutting program long enough to open a handful of U.S. branches.

Toronto-Dominion Bank, Canada's second-largest lender, is targeting wholesale banking in the U.S. after spending nine years building a network of retail branches from Maine to Florida.

First Horizon National (FHN) of Memphis, Tenn., is raising capital by issuing preferred stock. The parent of $25.5 billion-asset First Tennessee Bank announced Thursday an offering of depositary shares representing a fractional stake in its newly issued preferred stock.