For years, nearly all trading in the energy markets was in short- or medium-term contracts. But since 2004, the number of open long-term contracts has shot up, according to the Commodity Futures Trading Commission.
"What we saw in the past was sort of a herd mentality where all the traders on the floor would trade the first and second month," says NYMEX Floor Trader Anthony Grisanti of GRZ Energy. "What you're seeing now since the advent of electronic trading is a lot of brokers or locals on the floor don't trade the first month anymore. They keep an eye on the second and third month."