The Securities Industry Association, which represents investment bankers and brokers, has criticised the New York Stock Exchange's proposals to increase its use of electronic trading systems as "incomplete" and lacking important details.

In a letter to the Securities and Exchange Commission, the regulator responsible for approving the NYSE's proposal, Donald Kittell, the association's executive vice president, said: "Our intent is to express our concern that the current proposal provides an insufficient basis for the commission to grant approval of these sweeping changes."