The biggest class-action settlement offered by Prudential Securities in the scandal involving investors in 35 oil and gas limited partnerships has run into a significant roadblock.

In the past, governments determined movie budgets; now independent producers must put together complex packages involving domestic and Western European investors, the Council of Europe's Eurimages Fund and, above all, newly affluent television companies.

In fact, Mr. Coulson's association has already handled several cases involving foreign investors and American firms.

Arbitration lawyers say that Judge Scheindlin's decision will change the economics of arbitration cases involving investors seeking damages from investment banks over fraudulent research.

It is a type of tax shelter involving investors who take out bank loans that the government considers illegitimate.

The Conservation Fund says it has never heard of a larger price tag for such an effort involving governments and private investors.

Patrick F. Noonan, chairman of the Conservation Fund, said that the unusual deal, involving state governments, private investors and foundations, was needed to raise enough money to compete in the intensifying market for forest lands.

Traders and investors offered many rationales yesterday for the deepening skid, with the most common explanation involving overextended investors who have to sell stocks to pay off margin loans and tax bills.

Institutional trades are already accomplished with a "book entry" system, as are trades involving individual investors whose shares are held in brokerage accounts.

One person close to the bank board, who asked not to be named, confirmed that regulatory officials were under increasing pressure to announce deals in Texas involving large, well-capitalized investors.