Many are concerned, for example, about the time it takes some foreign exchanges to clear their trades.
Bear Stearns now says it clears trades for 2,400 firms, up from 725 in 1987.
This delineation may have made sense in 1970, when most brokerage firms cleared their own trades.
(They have arranged with another firm to clear their trades for a fee.)
Fossett cleared trades on various exchanges for 200 options traders.
Customers of a failed broker that used another firm to clear its trades and conduct administrative duties do not qualify.
Industry sources said First Options, which clears trades for hundreds of market makers, was particularly hard hit.
He said Nikko had applied to become a clearing firm, which would enable it to clear its own trades and act as a broker.
The exchange would say only that Amaranth's account and the firm that cleared its trades were in good standing.
The firm cleared its trades through Bear Stearns before collapsing last summer.