10 things you need to know before the opening bell

Here is what you need to know.

Trump threatens tariffs on all Chinese goods coming into America. President Donald Trump told CNBC's Joe Kernan in an interview aired Friday morning that he is ready to place tariffs on all $505 billion worth of Chinese goods coming into the US. ""I'm not doing this for politics, I'm doing this to do the right thing for our country," he said.

Trump breaks long-standing precedent of American presidents not commenting on the Fed. In the same interview on CNBC, Trump said he wasn't "thrilled" with the Federal Reserve raising interest rates.

There's one market that's vulnerable to Trump's tweets. Goldman Sachs crunched the numbers and found that Trump's tweets don't mean much to traders except in the soybeans market.

The unwind in the Chinese yuan's just getting started. The Chinese yuan has slumped 8% versus the US dollar since late March, and Sacha Tihanyi, deputy head of emerging markets strategy at TD Securities says, "We are revising our CNY target to reflect more weakness." Adding that Chinese policymakers have "become more amenable to a more rapid pace of depreciation than we initially assumed."

Copper drops to its lowest level in a year. The metal fell below $6,000 a metric ton on Thursday amid trade escalations and the unwinding of a $3 billion long position.

Comcast drops out of the $71 billion bidding war for 21st Century Fox assets. The cable provider said it is focusing its efforts on its fight with 21st Century Fox over the British broadcaster Sky.

Microsoft crushes earnings. The software company beat on both the top and bottom lines as its cloud unit saw revenue surge 23% year-over-year to $9.7 billion.

The scene inside Amazon was reportedly "chaotic" during the Prime Day glitches. The e-commerce giant held a 300-person conference call to try and deal with the glitches, CNBC reports.

Stock markets around the world are mostly lower. The S&P 500 is set to open down 0.23% near 2,798 as Germany's DAX (-0.8%) leads the losses in Europe. China's Shanghai Composite (+2.05%) paced the overnight gains in Asia.

Earnings reports keep coming. General Electric, Honeywell, and Schlumberger are among the companies reporting ahead of the opening bell.