West Texas Intermediate slid 2.9%, the biggest weekly decline since July, to $67.75 a barrel. That is after the U.S. crude benchmark had capped August with one of its sharpest rallies of the year, jumping more than 7% from the middle of the month. Brent, the global barometer for crude, ended last week 1% lower at $76.83, after nearing an almost four-year high. The rapid rise and fall in oil prices is a sign that investors are weighing conflicting signals in the market. On the one hand, robust developed-market economies have sustained demand for crude, while U.S. sanctions against Iran have led to shrinking oil exports from the country, draining global supplies. At the same time, emerging markets recently tipped into a bear market, spurring investors to closely monitor whether deeper declines will spill over into other assets. Emerging markets are the main source of growth in oil demand, […]