Here are five things you must know for Friday, Sept. 20: 

1. -- Stock Futures Up Modestly as U.S. and China Resume Talks

U.S. stock futures were up modestly Friday as investors debated the Federal Reserve's next policy move and looked for progress from the current round of U.S.-China trade talks.

Deputy trade leaders from both Washington and Beijing will conclude two days of talks on Friday, with discussions mostly focused on agriculture, as the world's two biggest economies attempt to build more goodwill heading into October's top-level negotiations in Beijing.

With both sides offering conciliatory delays on tariffs and agreeing to the first face-to-face talks since late June, investors are hoping the market's main risk overhang could soon be settled, allowing the strength of recent central bank rate cuts, including the Fed's cut of 25 basis points on Wednesday, to drive stocks higher.

Speaking engagements Friday from Federal Open Market Committee members John Williams and Eric Rosengren could provide investors with more clues on the central bank's next steps.

Meanwhile, the Fed also will conduct its fourth consecutive repo operation later Friday, offering another $75 billion in cash at its new rate of 1.7% in order to maintain the current fed funds rate at its reduced range of 1.75% to 2% following Wednesday's interest rate cut.

Contracts tied to the Dow Jones Industrial Average rose 46 points, futures for the S&P 500 gained 5.10 points, and Nasdaq futures were up 19.25 points.

Stocks finished mixed Thursday as trade worries reappeared and Wall Street grappled with mixed signals from the Fed about the future path of interest rates.

2. -- Facebook CEO Mark Zuckerberg Meets With Donald Trump

Facebook (FB) - Get Report CEO Mark Zuckerberg met with Donald Trump at the White House during a trip to Washington Thursday to meet with policymakers about future tech regulation.

"Mark is in Washington, D.C., meeting with policymakers to hear their concerns and talk about future internet regulation. He also had a good, constructive meeting with President Trump at the White House today," a Facebook spokesperson told CNBC in an email on Thursday.

Trump tweeted a photo and called the meeting "nice."

Facebook and other tech giants such as  (AMZN) - Get Report , Apple (AAPL) - Get Report and Alphabet (GOOGL) - Get Report  are under scrutiny from regulators and lawmakers as leaders of both parties in the House Judiciary Committee have requested private communications from top executives and other detailed information about their individual internal operations.

Facebook has been asked to turn over records of Zuckerberg's communications that may have discussed corporate rivals, including about companies Facebook has since acquired such as Instagram and WhatsApp.

Trump has been critical of Facebook, targeting Facebook's proposed Libra digital currency, and also because the president said he believes the social media platform is biased against conservatives.

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3. -- Apple's iPhone 11 Goes On Sale

Apple's iPhone 11 went on sale around the world Friday, with analysts betting the new smartphone will be a key sales driver for the tech giant heading into the key holiday season.

Apple unveiled the new suite of iPhones, which include new camera technology and longer battery life, at a gala event earlier in September.

Financial analysts keyed on the smartphone's aggressive pricing in U.S. dollars, which was discounted to previous rollouts, and the impact it would have on Apple's overall profit margins.

JPMorgan said Friday that it expects the iPhone 11, iPhone 11 Pro and iPhone 11 Pro Max to be the largest driver of Apple smartphone shipments over the next 12 months, and maintained its calendar 2019 forecast of 184 million units in sales of the entire iPhone suite. The bank sees that number improving to 195 million in 2020.

Apple's gross margins have been narrowing for the past few quarters, falling 700 basis points from the same period last year to 37.6% in the company's fiscal third quarter.

The Apple Watch Series 5 also went on sale Friday as the company looks for wearable technology to be a major component of sales growth in the coming years  as global smartphone demand wanes.

4. -- Beyond Meat Hires Tesla Executive for Chief Operating Officer Post

Beyond Meat (BYND) - Get Report  hired former Amazon and Tesla (TSLA) - Get Report executive Sanjay Shah to serve as chief operating officer at the plant-based meat company.

Shah served most recently as senior vice president of Tesla's solar business. He was there for a little more than a year. He went to Tesla from Amazon, where he oversaw fulfillment operations.

"Sanjay's focus on making operational excellence a sustained competitive advantage, his experience in and appetite for global expansion, along with shared values and a tireless work ethic, makes him a welcome addition to the Beyond Meat family," said Beyond Meat CEO Ethan Brown in a statement.

Shah will be responsible for Beyond Meat's global operations and production.

Beyond Meat declined 0.43% to $154.25 in premarket trading.

5. -- Global Climate Change Demonstrations Kick Off in Australia

Tens of thousands of protesters gathered Friday at rallies around Australia, kicking off a day of worldwide demonstrations calling for action to guard against climate change ahead of a United Nations summit next week in New York.

Australian demonstrators called for their nation, which is the world's largest exporter of coal and liquid natural gas, to take more drastic action to reduce greenhouse gas emissions.

Similar rallies were planned Friday in cities around the globe. In the United States, more than 800 events were planned Friday, while in Germany more than 400 rallies were expected, according to the Associated Press.

The protests are partly inspired by the activism of Swedish teenager Greta Thunberg, who has staged weekly demonstrations under the heading "Fridays for Future" over the past year, calling on world leaders to step up their efforts against climate change. CEO Jeff Bezos, meanwhile, unveiled Thursday a climate-change plan for the giant online retailer that will meet the goals of the U.N. Paris Agreement 10 years ahead of schedule.

The plan was a response to an employee proposal at the company's annual meeting in May to develop a comprehensive climate-change plan to reduce the Seattle company's carbon footprint.

The plan came  a day ahead of a planned walkout at numerous tech companies by employees concerned about global climate change. Workers at Amazon, Alphabet, Facebook and Microsoft (MSFT) - Get Report are expected to take part in walkouts Friday meant to pressure the tech industry to do more to address climate change.

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