When Congress passed a new financial regulation bill last month, it sought to prevent federally insured banks from making speculative bets using their own money. But that will not stop banks from making bets that some critics deem risky, even as the rules go into effect over the next few years.

That is because many such bets — on the direction of the stock market or the price of coal, for example — are done on behalf of clients. So, the banks say, they will continue to be allowable despite the new restrictions.

Indeed, several trades that were made on behalf of clients went bad for the banks even as the new rules were being debated in Washington this year. JPMorgan Chase and Goldman Sachs, for example, each lost more than $100 million on transactions handled for customers in the period from April to July.

Blowups like these, only larger, contributed to the financial crisis and forced the federal government to spend billions of dollars to bail out financial institutions. Yet analysts are quick to point out that many of those transactions were handled by the banks, ostensibly to serve clients.