A rare opening of an export window for crude moving from the U.S. Gulf to Western Europe has caused a flurry of interest among oil traders, with at least two securing vessels. On Tuesday, global marker Brent’s premium traded to as much as $2.50 a barrel over U.S. crude futures, the most since late February. The widening of the premium presented an arbitrage opportunity, prompting oil traders to secure vessels to send crude eastward across the Atlantic, sources said. The shipments are shaping up to be one of the more notable batches of U.S. crude exports bound for Europe since a ban on them was lifted in December 2015. Astra Transcor Energy, also known as Astra Oil, has secured the Nantucket, a Suezmax, loading heavy Canadian crude in Houston on Aug. 30 to the United Kingdom or Mediterranean, according to two sources familiar with the matter and Thomson Reuters […]