The China economic slowdown that has rattled global markets is also shaking the fortunes of multinationals that do business here . Those that fed China’s traditional boom industries of infrastructure, energy and steel—like Anglo-Australian miner BHP Billiton Ltd. BHP 3.52 % and French energy-equipment maker Schneider Electric SU 2.22 % SE—are suffering precipitous falls in revenue there after years when their profits were boosted by the country’s 10%-plus economic growth. Many also face heavy write-downs as investment plans predicated on surging China demand look increasingly unrealistic as the country’s growth slows. “We’re spending as much as we always do,” said Zhen Lin, a 27-year-old magazine editor on maternity leave, emerging from a Beijing supermarket with a cart half full of groceries. Ms. Lin said she eats out several times a week and isn’t holding back on her spending. Among the purchases she is planning: a new computer this year […]