The Leviathan gas field, 84 miles from Israel's northern coast and three miles below the Mediterranean seabed, is the largest deepwater gas find in the last ten years, estimated to contain 16 trillion cubic feet of gas. Houston based Noble Energy is an independent oil company that is operating the field. Before this find the US Geological Survey had released its first assessment of the zone- the Levant basin stretching offshore in the Mediterranean- estimating that it contained 1.7 billon barrels of oil and 122 trillion cubic feet of gas. This is equal to half the proven reserves in the US. Before this find Israel had failed to find much oil and gas and big oil and gas companies had stayed away not wanting to disturb relations with Arab and Iranian partners. Because of a 1952 petroleum law, Israel offers very attractive terms to oil companies such as Noble, with low royalties and low corporate taxes on exploration. Now the Israeli government is considering changing the terms retroactively on previously assigned leases. In November 2010, Finance Minister Steinitz says a government appointed committee has made preliminary recommendations to abolish tax breaks for energy firms and impose tax increases of 20% to 60% on windfall profits. Israel's Securities Authority has also started to clamp down on trading irregularities, and raided the offices of two enegy exploration companies. Rumors of big finds have set off a speculative frenzy in Israel's stock market. The energy index of the Tel Aviv stock exchange went up by 1700% in 2010, and energy stocks account for half of the activity on the exchange. ...