The consumer lending business at many of the nation's commercial banks  is faltering. Although margins for many products remain strong, weak demand   coupled with the competitive challenge of nonbanks, product substitutes,   and securitized offerings are slowing the growth of bank loan footings.   From 1991 through 1993, the compound annual growth rate of bank revolving   consumer loans came to just under 4%, compared to a 10-year figure of 11.1%   (Rates for 1994 will shortly become available and are not expected to   change the basic trend.)             
In 1984, banks held 59% of outstanding consumer revolving loans; by  1993, that share had fallen to 49%. The bank share of auto loans dropped   from 48% to 44% over the same period. In mortgage originations, banks have   been taking share away from thrifts over the course of the last decade,   although thrifts have recently recouped a bit of this loss. Both   intermediaries, however, have been losing to the mortgage companies. Thus,   in 1993, banks accounted for 26% of originations versus a 41% share in   1987.             
  
In calculating true loan growth trends for individual banks, it is  essential to adjust the totals for the impact of mergers and acquisitions   as well as for asset securitization. FMCG's compilation of merger-adjusted   and securitization-adjusted growth figures for a sample of 30 of the top   money-center and superregional banks shows that the average institution   managed only a 2.3% compound annual increase in consumer loans outstanding   from 1991 through 1993.           
As one might expect in most analyses of retail banking, however, the  figures are quite skewed. Although average growth is disappointing, there   are a substantial number of banks that greatly exceeded the average during   this period. In fact, 12 of the 30 had acquisition-adjusted annual rates of   growth that topped 12%. Conversely, there are a large number whose consumer   lending totals actually dropped.         
  
Growth leaders for the 1991-1993 period (figures are compound annual  rates) include Signet (26%), Banc One (18%), Fifth Third (17%), First   Chicago (17%) and Bank of New York (15%). Apart from their disdain for   merely average performance, what factors predispose banks like these to   excel while so many others languish? The short answer (or at least one   short answer) is that they specialize. The top dozen high-growth consumer   lending banks can be subdivided into three groups - card banks, other   specialty banks, and only a few across-the-board consumer lenders.             
About half of the growth leaders are card specialists that often spurn  other areas. Thus, from 1991 through 1993, BONY grew its card portfolio by   32% per annum, but its home-equity loan and line business by only 4%. Other   specialist types eschew cards just as emphatically. Fifth Third grew its   installment loan portfolio by 21%, but its card portfolio by only 2%.       
The top card banks have evolved a formula that probably will be emulated  by most successful consumer-lending banks for the rest of the decade. These   banks understand that the profitability of their customer populations is   just as skewed as are bank growth trends. Where these banks excel is in   their capacity to identify which consumers are likely to be profitable and   which will probably prove unprofitable. Having done so, they proceed to   alter their products to attract and retain a disproportionate share of the   former.             
  
The strategy is simply called customer data base management. The best  credit card institutions begin by employing regression models that predict   the potential for profitable purchase - i.e., the likelihood of being a   "revolver" - in various market segments. Then they hypothesize changes in   product features or distribution mechanisms that will appeal to those   customers most apt to revolve without defaulting or going delinquent. In   credit cards, such hypothesized changes run the gamut from lower rates to   gifts or bonus points.             
Next the banks select appropriate segments for testing and run a pilot  test on a subsegment or "cell." Finally, they evaluate the results and roll   out the successful tests to ever larger portions of the customer base. The   net result is the ability to predict actuarially the product   characteristics, service features, and prices that will stimulate enhanced   profitable usage and lower customer attrition rates.         
This type of approach - it is really just the application of the old-  fashioned scientific method - is also beginning to be used by leaders in   the mortgage business and by some in home-equity lines of credit and other   products. And when applied to the deposit side of retail, the approach   could reverse a decade-long slide in profitability.       
Additionally, creative data-base marketing and customer management may  spawn an entirely new business opportunity. Skilled customer data base   managers are beginning to offer themselves as potential alliance partners   to banks that have large customer bases, but precious little knowledge   about them. Thus, the leaders in scientific customer management will be   twice blessed - blessed in what they can do and also in what they can   teach. So endowed, at least a handful of top consumer lenders will never   have to endure the disappointment of merely average performance.             
  
Mr. Zizka is a managing vice president for First Manhattan Consulting  Group, New York. Mr. Rose, formerly senior columnist for this newspaper, is   also associated with First Manhattan.