Prices have fallen more than 20 per cent from their levels in early January, which they last touched in the summer of 2015. A decline of more than 20 per cent from a most recent high is typically considered a bear market.

U.S. crude for July delivery lost 97 cents, or 2.2%, to $43.23 a barrel on the New York Mercantile Exchange, trading at prices it hasn't settled below since Aug. 10. A settlement at $43.56 a barrel or lower put oil into a bear market, which means it has lost 20% or more since the recent high, a nearly one-year high on Feb. 23.

Brent futures were up 4 cents at $46.95 at 0214 GMT. On Monday, they fell 46 cents, or 1 percent, to settle at $46.91 a barrel. That was their lowest since Nov. 29, the day before the Organization of the Petroleum Exporting Countries (OPEC) and other producers agreed to cut output for six months from January. U.S. West Texas Intermediate crude futures were down 1 cent at $44.19 a barrel. They declined 54 cents, or 1.2 percent in the previous session, to settle at $44.20 per barrel, the lowest close since Nov. 14. The July contract will expire on Tuesday and August will become the front-month.

Brent crude oil LCOc1 was up 48 cents at $48.34 a barrel by 12:17 p.m. EDT. U.S. crude CLc1 was 39 cents higher at $46.04 a barrel. U.S. crude and Brent benchmarks remained on track for weekly declines of more than 3 percent, pressured by big U.S. inventories and heavy worldwide flows.

Brent crude LCOc1 was up 43 cents by 0900 GMT at $48.49 a barrel, having fallen 4 percent the day before, while U.S. crude futures CLc1 rose 38 cents to $46.10 a barrel.

Brent crude prices LCOc1 were at $49.70 per barrel at 1351 GMT, down 42 cents. Brent is about 8 percent below its open on May 25, when OPEC and other producers agreed to extend oil output cuts through to the first quarter of 2018. U.S. light crude prices CLc1 were at $47.69 per barrel, down 50 cents.

EIA forecasts Brent spot prices to average $53/b in 2017 and $56/b in 2018.

Global benchmark Brent LCOc1 advanced 1.1 percent to $50.48 a barrel. U.S. oil CLc1 also climbed 1 percent to $48.17.

A crude price in the $50s is the new reality for bosses of some of the world’s largest producers as output caps from OPEC and its allies are balanced out by rising U.S. shale.

International Brent crude futures were at $50.96 per barrel at 0646 GMT on Friday, up 19 cents, or 0.37 percent, from their last close. U.S. West Texas Intermediate (WTI) crude futures were at $48.01 per barrel, up 18 cents, or 0.38 percent.