Summary: Here's everything you need to know before Monday's opening bell: China announced new tariffs of up to 25% on U.S. products such as pork, fruit, nuts and wine. Walmart has reportedly begun early stage talks to buy Humana . Saks Fifth Avenue and Lord & Taylor suffered data breaches with more than 5 million credit and debit cards exposed. A subsidiary that runs FirstEnergy nuclear and coal-fired power plants filed for bankruptcy. U.S. stock futures pointed lower as Wall Street returned from its long weekend. Check out the Morning Jolt for more of the day's biggest headlines:
