Goldman Sachs slashed its crude oil price forecasts for 2016 to 2020, citing improved U.S. shale efficiency meeting global oil demand, coupled with unimpeded OPEC productivity. However, the U.S. investment bank, in a note published on Saturday, raised its view of the average 2015 Brent price to $58 per barrel from its earlier forecast of $52, and lifted its outlook for the average WTI price to $52 per barrel from $48. The bank assumes a $5 per barrel Brent-WTI spread through 2016-2020, consistent with transportation economics. On May 12, the U.S. investment bank had cautioned that the recent rally in oil prices was ‘premature,’ and a sequential weakening of prices was required for the rebalancing of the market to resume. Oil prices have recovered this year, after sharp falls prior to 2015. Benchmark Brent crude oil futures has rallied about 12 percent since the beginning of the year, and are up by about 40 percent from their 2015 low.