China’s central bank devalued its tightly controlled currency, causing its biggest one-day loss in two decades, as the world’s second-largest economy continues to sputter. Chinese authorities said the change would help drive the currency toward more market-driven movements. The move also signaled the government’s growing worry about slow growth . A shift toward a weaker currency could help flagging exports at a time when many other efforts to boost the economy haven’t proven very effective. China’s yuan has been on an upward track for a decade, during which the country’s economy grew to be the second largest in the world and the currency gained importance globally. The devaluation Tuesday was the most significant downward adjustment to the yuan since 1994, when as part of a break from Communist state planning, Beijing let the currency fall by one-third. China sets a midpoint for the value of the yuan against the […]