Here is what you need to know.

Yellen speaks at Jackson Hole. Fed Chair Janet Yellen will deliver her speech, titled “Financial Stability,” at 10 a.m. ET and will be followed by European Central Bank head Mario Draghi at 3 p.m. ET.

Hurricane Harvey threatens oil refineries in the Gulf of Mexico. West Texas Intermediate crude oil trades up 0.65% at $47.74 a barrel as Hurricane Harvey bears down on Texas.

Japanese price pressures are building. Core consumer prices rose at a 0.5% year-over-year rate, their fastest since March 2015, but remain well below the Bank of Japan’s 2% target.

The market is starting to freak out about the debt ceiling. The yield on Treasury bills due October 5 jumped to 1.175% on Thursday, its highest since August 10, over anxiety Congress won’t be able to reach an agreement to raise the debt ceiling.

The most important pillar of the bull market is starting to crumble. Corporate earnings growth, historically the biggest contributor to share-price appreciation, has nowhere to go but down, according to Nicholas Bohnsack, the president and head of quantitative research at Strategas.

Amazon once again flashes its ability to destroy the competition. Amazon announced it would close on its Whole Foods acquisition on Monday and immediately slash prices, sending rival grocery-store stocks sharply lower.

Samsung heir Jay Lee receives a prison sentence. Lee was sentenced to five years in a South Korean prison for paying bribes to President Park Geun-hye in anticipation of favors, Reuters says.

Stock markets around the world are higher. Hong Kong's Hang Seng (+1.2%) led the gains in Asia, and Germany's DAX (+0.41%) paces the advance in Europe. The S&P 500 is set to open higher by 0.33% near 2,447.

Earnings reports trickle out. Big Lots reports ahead of the opening bell.

US economic data is light. Durable-goods orders will be released at 8:30 a.m. ET. The US 10-year yield is unchanged at 2.19%.