The Dow Jones Industrial Average fell by over 600 points after opening on Monday, thanks in large part to a poor performance from the technology sector. According to a report from NBC, the NASDAQ and the S&P 500 also finished in the red. However, their losses were minor compared to the Dow.

Tech juggernaut Apple lead the plummet, as shares of the company dropped by five percent at times during the day. Compounding the problem is current geopolitical instability, rising interest rates, and the ongoing wildfires in California — which all contributed to Wall Street’s feeble Monday performance.

Apple received lousy news even before the morning bell was rung. According to a report from Market Watch, J.P. Morgan reduced its estimate of Apple’s stock price, which kicked off the tech firm’s tough day. Shortly after, manufacturing firm Lumentum stated that the company would be producing less than anticipated numbers of “laser diodes,” after a “large customer” revised an order. Lumentum is long known to be a principal supplier of Apple iPhone parts, and experts speculated that Lumentum’s announcement signaled that iPhone sales have been weaker than anticipated. Although many have surmised that Apple’s new iPhones flopped commercially, the company is still closely guarding its exact sales numbers, which only leads to more speculation. For its part, Lumentum has not confirmed nor denied the rumors, but analysts believe that the revised orders could mean a reduction of iPhone sales by up to 30%.

While Apple may have led the fall, other tech giants quickly followed suit. The other three companies which make up the FANG stocks (Facebook, Apple, Netflix, and Google) all saw losses throughout the day. According to a report from the USA Today, shares of less visible — but still crucial — tech firms like Advanced Micro Devices, Nvidia, and Micron Technology also closed in the red. Many believe this is evidence that the tariffs on China are causing blowback consequences.

Critical reports about the US economy, such as the consumer price index, the Atlanta Fed Business Inflation Expectations report, and retail sales report are all scheduled to be released later this week. These documents will paint a more complete picture of the effects the Sino-American trade conflict may be having. An equally important Chinese report concerning the country’s “retail sales and industrial production” is slated to be published this week as well. Experts are waiting for that data before they gauge the tariffs’ impacts on the Asian superpower’s economy.

“That will tell us what is happening to the Chinese economy and if the trade conflict is having an effect on them, too,” said Independent Advisor Alliance’s chief investment officer Chris Zaccarelli while speaking to the USA Today.