LONDON, Aug. 29 -- When Wall Street retreated on Friday after Kevin Warsh's hawkish Jackson Hole speech pushed September rate hike odds to 48%, the FTSE 100 had a different calculation to make. The London benchmark closed up 0.23% at 10,817.72, a modest advance that reflected something New York investors had no comparable protection from: an index built on energy majors that price in dollars and report earnings in sterling.

Shell PLC and BP PLC, the two British oil and gas companies that together account for a significant share of the FTSE 100's total market weight, moved higher on Friday as crude oil prices steadied and the weaker pound amplified their dollar-denominated revenues in sterling terms. That currency translation effect is a ...