Low crude prices are finally squeezing refineries’ margins

The oil industry has seen waves of consolidation in the two years since crude prices plunged: oil producers, pipeline companies, companies that service oil fields. But refineries held up for a long time. For them, low prices for oil — their raw material — meant higher profits. But now the changing economics of oil are changing the economics of refining. Tesoro announced it’s buying Western Refining for about $4 billion.