Via Boston Globe

US index futures signaled losses will cascade in the world’s biggest stock market after equities ended last week down the most in almost four years.

In a broad selloff spanning all industries, stocks including Apple Inc. and Netflix Inc. slid at least 5.3 percent, while slumps in Gilead Sciences Inc. and Biogen Inc. indicated a selloff in biotechnology shares won’t abate. ConocoPhillips and Schlumberger Ltd. lost more than 3.2 percent as crude fell further.

Contracts on the Standard & Poor’s 500 Index due in September slid 3.5 percent to 1,902.50 at 8 a.m. in New York. Futures on the Nasdaq 100 Index fell 5 percent and those on the Dow Jones Industrial Average retreated 3.7 percent.

“GDP growth in the US and euro zone economies just isn’t strong enough to prevent a global disinflationary shock from accumulating,” Thomas Thygesen, SEB’s head of cross-asset strategy, said by phone from Copenhagen. “People have realized there could be further weakness in the Chinese currency. They don’t seem in control of the situation and we could see feedback loops that haunt the US.”

Calm in the US market shattered last week, with volatility soaring by the most on record as the Dow entered a correction and investors dumped the biggest winners of 2015. A gauge of volatility expectations more than doubled last week. Shares succumbed to a global selloff that’s wiped more than $5 trillion off the value of equities around the world since China’s shock currency devaluation on Aug. 11.