Oil prices reached an 18-month high on the Merc.

As tensions escalated in the strategic Persian Gulf oil channel, prices surged by 32 cents to $20.93 a barrel on the New York Mercantile Exchange. Britain’s North Sea Brent crude shot up by 45 cents to $19.40 a barrel on the European spot market, where oil is sold to the highest bidder. On the Merc, West Texas Intermediate--the benchmark U.S. crude for August delivery--ended near its high for the day at $20.93 a barrel. It was the best close since the crude finished at $21.27 a barrel on Jan. 20, 1986.