The latest trigger was currency jitters, but Thursday’s plunge in Chinese stocks was just one in a series of aftershocks from last year’s boom and bust that could shake markets for months to come. Investor anxiety over economic weakness and a possible glut of unwanted shares flooding the market have complicated Beijing’s efforts to withdraw emergency controls imposed after Chinese stock prices collapsed in June.

On Thursday, trading halted for the day after a stock index fell 7 percent a half-hour into the trading day. It was this week’s second daylong suspension after a plunge in prices Monday tripped the same “circuit breakers” that were introduced Jan. 1.

The benchmark Shanghai Composite Index more than doubled between late 2014 and June, then dived 30 percent. Supported by a multibillion-dollar government intervention, the market rose almost 25 percent in the final months of 2015, only to collapse in the new year. That left the main index down 15 percent from its December peak. FULL REPORT