Stocks tumble as tech, commodities trigger fears

U.S. stocks had their worst day in seven weeks Wednesday amid a broad decline in global equities as technology shares were roiled by disappointing results from Chinese internet giant Tencent Holdings and copper sank into a bear market, weighing on commodities. Crude oil slipped below $65 a barrel following a report that American stockpiles rose the most since March 2017.

The S&P 500 index declined for the fifth time in six sessions, while the Nasdaq 100 index posted the weakest performance among major U.S. benchmarks. Strong retail sales figures did little to mollify investors, as Macy's Inc. plummeted 16%, the most since May 2017, despite beating expectations. Tencent's first profit decline in at least a decade also rattled emerging-market equities.

The S&P 500 slumped 0.8% to 2,818.39, the biggest decline since June, and the Nasdaq 100 dropped 1.2%. The Stoxx Europe 600 Index decreased 1.4% to the lowest in more than a month. The MSCI All-Country World Index dipped 1.1% to the lowest in five weeks. The MSCI Emerging Market Index fell 1.8%, reaching the lowest since July 2017.

"Tech stocks are pulling the markets lower," said Naeem Aslam, chief market analyst at TF Global Markets U.K. in London. "We are seeing investors becoming more concerned about the geopolitics."

The U.S. yield curve's torrid run toward inversion remains squarely on track as investors seemingly take advantage of any steepening to pile further into the flattener trade.

The spread between two- and 10-year Treasury yields at midday Wednesday narrowed to the least since August 2007 as traders continue to crush a brief bout of steepening seen in the past month. Concern that Turkey-induced turmoil spreading across emerging markets could spark global contagion hasn't derailed investors' expectations that the Federal Reserve will keep tightening monetary policy, driving shorter-dated U.S. yields higher.

The yield gap between two- and 10-year maturities had rebounded to just over 33 basis points both in late July and earlier this month before renewing its compression. The differential narrowed to as little as 23.4 basis points Wednesday, aided by a better-than-expected U.S. retail sales print.

The yield on 10-year Treasuries declined 4 basis points to 2.8569%, the lowest in a month. Germany's 10-year yield slid two basis points to 0.304%. Britain's 10-year yield decreased four basis point to 1.225%.

Tesla Inc. dropped more than 2.5% after a report that the U.S. Securities and Exchange Commission sent a subpoena to the company regarding Elon Musk's privatization plans and his comments about having secured funding.

Raw-materials producers dragged down European shares as copper and zinc sank to the lowest in more than a year. In Turkey, the lira gained after the country's banking regulator moved to deter short-selling in the currency. While the nation's assets stabilized, other emerging market currencies continued to buckle as President Recep Tayyip Erdogan intensified a diplomatic feud with U.S. President Donald Trump by issuing a series of new import tariffs.

With the bull market in American stocks just a week away from becoming the longest in history, investors have turned increasingly cautious amid lingering global trade tensions. Markets have been rocked over the past week as turmoil in Turkey weighed on sentiment across many emerging and developed nation assets. Qatar promised Wednesday to invest $15 billion in the Turkish economy to help the country avert a financial crisis.

Elsewhere, Hong Kong intervened to defend its peg to the dollar for the first time in three months after the local currency fell to the weak end of its trading band. Several markets, including Poland and India, were closed for a holiday.