President Obama has unilaterally banned oil and gas drilling throughout the Arctic and in large parts of the Atlantic Seaboard. The New York Times described the move as an attempt “to nail down an environmental legacy that cannot quickly be reversed by Donald J. Trump.”

Oil prices have risen around 1% since the drilling ban, and ETFs that track oil have followed suit. United States Oil (USO) and ProShares Ultra Bloomberg Crude Oil (UCO) rose over 1.1% and 2.2% respectively in early morning trading on Tuesday while investors digest the news. The energy sector has also seen some gains, driving the Energy Select Sector SPDR (XLE) up 0.4% on Thursday morning.

Obama’s ban depends on an authority granted in 1953’s Outer Continental Shelf Lands Act. According to that law, the president can “withdraw from disposition any of the unleased lands of the outer Continental Shelf,” effectively banning any energy production in those areas. Some analysts expect the ban to be challenged in a lawsuit, but it could take years before a judgment can reverse Obama’s decision.

The move has caused growing expectations of lower oil supplies in the United States, which has seen a continued glut of the commodity. Crude oil continues to flow into refineries at a historically high level.  According to the U.S. Energy Information Administration, refineries got 16.7 million barrels per day last week, which contributed to a 2.3 million barrel increase in oil inventories. Analysts had expected inventories to fall by 2.5 million barrels.

Additionally, the Organization for the Petroleum Exporting Countries (OPEC) has been working closely with non-OPEC nations to lower oil production around the world. The cartel’s move to cut production has successfully driven oil prices higher. Since the agreement was announced, WTI futures have risen 16%. (See also: OPEC Cuts Boost USO, UCO.)

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