Smorgasbord competitors: how great a threat to banks?

William F. Ford, president of the Federal Reserve Bank of Atlanta, confessed he had engaged in a bit of ''rabble-rousing.'' He added: ''You need to have a little fun once in a while.''

What the central banker had done was to tell an audience of commercial bankers that they were overrating their new competitors in finance, such as Sears, Roebuck & Co., the department store chain that bought Dean Witter, the brokerage firm, and Coldwell Banker, the real estate company.

''If we look at the situation objectively,'' he said, ''we can see that the industries most aggressive in competing against banks often seem to be diversifying out of weakness rather than strength, weakness that might well limit their ability to threaten banks.''

To point out the difficulty Sears might have in merging and marketing such disparate activities as retail merchandising, brokerage and real estate, he and his staff composed a few sales mottoes:

''Buy your stocks where you buy your socks.''

''If you lose your shirt, we'll sell you another one.''

''Buy your house where you bought your blouse.''

In effect, Mr. Ford was calling the bankers crybabies for their common laments about the new competition. Nonetheless, the speech was popular enough that the former economist for the Wells Fargo Bank in San Francisco has since had some 40 invitations to speak to various banking audiences. ''They must like being tortured or something,'' he joked.

The commercial bankers' complaint is that the Fed's Regulation Q puts a ceiling on time deposit interest rates and prevents them from competing aggressively with money market funds and others for deposits; that the Glass-Steagall Act keeps them from innovating new services because it prohibits banks from entering the securities business; and that the McFadden Act with its prohibition of interstate deposit banking and the Douglas Amendments prevents them from following their natural markets across state lines.

Nonbank institutions, they argue, are much less regulated and seem to be able to operate more freely than banks in the nation's financial markets. So, the bankers maintain, Congress should establish ''a level playing field'' in the financial area by granting them more powers.

Earlier this month, for instance, the leaders of the American Bankers Association reached a consensus on how they would like Congress to expand their banking powers ''to make banking competitive in the 1980s.'' They, for instance, want the ''removal of impediments to the rational pricing of banking services'' such as Regulation Q, state usury statutes that set ceilings on loan interest charges, and state prohibitions of ''due on sale'' clauses in mortgage contracts -- the laws that enable householders to pass on their cheap mortgages to buyers when selling their homes.

The Senate Banking Committee under Sen. Jake Garn (R) of Utah has been considering banking decontrol regulation. But the conflict among the powerful lobbies of the banks, the savings-and-loan associations, the mutual savings banks, and the securities industries has been so sharp as to produce a stalemate.

New York's Citicorp has attempted to publicize the ''threats'' to banks by publishing the ''Old Bank Robbers' Guide to Where the New Money Is,'' a humorous outline of the financial activities of competing institutions ranging from the D. H. Baldwin Company (famous for its pianos) to J. C. Penney, Greyhound, Merrill Lynch, and National Steel. The idea is that robbers might be missing new accumulations of money outside the banks.

The Atlanta Fed's Mr. Ford admitted that there may be some justification for leveling the financial playing field. But, he added, bank earnings have outpaced such ''new competitors'' as savings-and-loan associations, the stockbrokers, insurance companies, and Sears, Roebuck over the past 20 years. In fact, bank earnings have not experienced a decline in net income after taxes in 20 years.

Moreover, between 1972 and 1980 bank credit cards posted a significant gain in market share over Sears cards. Sears remains an exception. ''. . . Sears is playing defense, not offense,'' Ford concluded.

Looking at the threat from the securities industry, he reckoned that money market funds may have hurt S&Ls, but ''may not represent a net drain of funds on the banking industry.'' That's because the funds take money from S&Ls, mutual savings banks, and elsewhere and use much of that money to buy commercial bank certificates of deposit.

Despite his ''fun'' with the question of competition, Ford is concerned about the trend of conglomerate firms to move into the financial area. He wonders if the United States could end up with ''zaibatsu,'' as in Japan, or ''universal banking'' as in West Germany. In both countries, banks own groups of industrial concerns, or vice versa. Some argue that the groups wield too much economic power through their control of large chunks of both industry and finance.

''This trend requires some study and thought,'' Ford says.