INVESTMENT PRODUCTS: MARKETING FIRMS for investment products, which help banks sell brokerage products, are broadening their product lines and devising innovative services in a bid to attract and retain clients. Page 14 WELLS FARGO & Co. is joining the handful of companies offering brokerage accounts that diversify assets among a range of mutual funds. Page 15 WASHINGTON: A FEDERAL APPEALS court has ruled that the law allowing banks to ignore state restrictions on credit card interest rates also applies to the increasingly popular income tax refund loans. The ruling eases making the loans to out-of-state customers. Page 2 TECHNOLOGY: A SURVEY of 118 community financial institutions in about 10 western states suggests that many smaller banks are dissatisfied with the way technology providers enhance and support their core processing products. Page 4 IBM's SYSTEM 36 midrange computer is considered outdated by some, but many community banks continue to find the system reliable and cost-effective. Page 4 REGIONAL BANKING: AS INTEREST RATES rose last year, banks were able to lure customers back into certificates of deposit and other savings instruments. But this achievement could display its downside in 1995, as rising deposit costs strain net interest margins. Page 6 COMMUNITY BANKING: THE FIRST OVERHAUL of the U.S. Department of Agriculture in 130 years will be a boon for banks whose hometowns gain regional service centers and a bane for those where the agency is closing 1,274 field offices. Page 8 MAKING SURE your resources are allocated appropriately to customer-driven functions and using your independence to mitigate an acquirer's premium for consolidation are key litmus tests for determining whether your bank can remain independent, write consultants Marilyn R. Seyman and Steven P. Williams. Page 9 MORTGAGES: WITH ORIGINATION volume slumping, mortgage companies are not paying out the fat yearend bonuses that have been typical recently, but most employees are just glad to be working. Page 12 FOUR HOME LENDING franchises were started last year and seem to be expanding, but today's weak mortgage market is making for very slow growth. Page 13 CREDIT/DEBIT/ATMs: FIRST NATIONAL Bank of Commerce signed a contract to issue and process proprietary credit cards for the U.S. Air Force. Page 10 PLUS AND CIRRUS have each surpassed the one-billion-transaction mark and predict their two-billionth transactions will take place in less than three years. Page 10 FINANCE: CONTRADICTING conventional wisdom about the banking industry, a new study finds little correlation between mergers and efficiency gains. Back page MELLON BANK replaced First Fidelity Bancorp on Lehman Brothers' recommended list as an analyst downgraded First Fidelity from "buy" to "outperform." Back page