But relying on the market to discipline financial institutions is generally unacceptable. It is too blunt a weapon for financial institutions, which are thinly capitalized and closely linked through myriads of transactions with other institutions.

Financial institutions are the holders and, therefore, the guardians of our savings and temporary funds, a unique public responsibility. Truly letting the marketplace discipline the financial system would mean acquiescing in an avalanche of potential failures - including many salvageable financial institutions and many of their customers.

The excesses of financial entrepreneurship have been abetted by a kind of ''hollowing out'' of the financial regulatory system. Because of piecemeal legislation, official supervision and regulation is highly fragmented. That has meant heavy and inefficient overlapping authority in some areas and enormous regulatory gaps in other areas.

Specifically, the two agencies with responsibility for the securities industry, the Securities and Exchange Commission and the Federal Reserve Board, hold opposite - and probably irreconcilable - theories of financial regulation and supervision.

In a nutshell, the Fed believes that the holding-company parent and all affiliates of a bank or securities firm ought to be supervised on a consolidated basis. The S.E.C.'s legal authority is narrowly focused on the broker/ dealer operation of a securities firm.

Thus, under the terms of its mandate from the S.E.C., the New York Stock Exchange must concentrate its surveillance on the broker/dealer. It has little authority to go into other affiliates of the broker/dealer's parent, even if they are involved in financial activities.

This regulatory fragmentation, and the loopholes it provides, has not been lost on Wall Street. The leading securities houses have all sought to increase their financial leverage by forming elaborate holding companies. To this end, they use creative, though permissible, accounting techniques to hide from public view their gross asset and liability structures.