Here are five things you must know for Thursday, Aug. 30:

1. -- Stocks Tumble Amid Worries Over Trade Deal With China

U.S. stock futures fell on Thursday, Aug. 30, and global stocks traded lower as markets retreated after four consecutive record-setting sessions on Wall Street, amid concerns that the White House's focus on trade talks with its North American partners would push a potential deal with China further into the future.

With Canada back at the negotiating table this week ahead of a deadline of Friday, Aug. 31, set by Donald Trump to reach an agreement that would overhaul the current arrangement with the three north American economies, investors have grown concerned that the U.S. focus on both a NAFTA deal and the impending mid-term elections will put the stalled trade talks with China further down on Trump's agenda.

Contracts tied to the Dow Jones Industrial Average  fell 59 points, futures for the S&P 500  were down 3.75 points, and Nasdaq futures tumbled 11.75 points.

Stocks surged Wednesday, Aug. 29, with the S&P 500 and Nasdaq setting record closing highs as second-quarter U.S. GDP growth was revised upward to 4.2%.

The economic calendar in the U.S. on Thursday includes weekly Jobless Claims at 8:30 a.m. ET, and Personal Income and Outlays for July at 8:30 a.m.

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2. -- Salesforce Tumbles on Soft Guidance Inc. (CRM)  fell 3.4% in premarket trading after second-quarter earnings beat analysts' forecasts but the customer-relationship management software company issued soft guidance for the third quarter.

Salesforce said it expects fiscal third-quarter revenue of around $3.36 billion but noted that ongoing increases in marketing and research and development costs would likely bring its bottom line in at a range of 49 cents to 50 cents a share, below Wall Street forecasts of around 54 cents.

Earnings in the second quarter were 71 cents a share on revenue of $3.28 billion, higher than forecasts that called for earnings of 47 cents a share on revenue of $3.23 billion. After backing out a 14-cent gain related to the accounting of "strategic investments," the earnings beat in the second quarter was 10 cents.

For the full year, Salesforce expects to earn between $2.50 and $2.52 a share on revenue between $13.125 billion and $13.175 billion.

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3. -- Abercrombie, Lululemon and Campbell Soup Report Earnings

Campbell Soup Co. (CPB) said Thursday it was selling its two international units and its fresh foods business, a move that stemmed from a three-month board strategic review on what direction the soup maker would take. The much-anticipated announcement was made as Third Point's Dan Loeb and a descendant of the company's one-time president and owner wanted to see Campbell Soup sell itself.

Campbell Soup also reported fiscal fourth-quarter earnings of 25 cents a share, 1 cent ahead of analysts' estimates. Revenue was $2.2 billion vs. estimates of $2.24 billion. The stock fell 2.4% in premarket trading.

Dollar General Corp. (DG)  reported second-quarter profit of $1.52 a share, 3 cents ahead of estimates, and same-store sales rose 3.7%. The retailer said it expects fiscal-year sales to rise 9% to 9.3%. The stock fell 2.5% in premarket trading.

Dollar Tree Inc. (DLTR) fell 5.2% after second-quarter earnings came in just shy of estimates and the company lowered the top end of its full-year earnings guidance.

Ciena Corp. (CIEN)  posted third-quarter adjusted earnings of 48 cents a share, beating estimates by 12 cents. The stock rose 7.7%.

Abercrombie & Fitch Co. (ANF)  earned an adjusted 6 cents a share in its second quarter vs. an estimated loss of 4 cents. Sales of $842.4 million in the quarter came in below forecasts of $845.1 million. Shares fell 12.5%.

4. -- Apple Buys Maker of Lenses of Augmented Reality Glasses

Apple Inc. (AAPL) confirmed Wednesday it acquired Akonia Holographics, a startup from Longmont, Colo., that is focused on making lenses for augmented reality glasses.

"Apple buys smaller companies from time to time, and we generally don't discuss our purpose or plans," the iPhone maker said in a statement to Reuters.

Apple has a history of buying smaller companies whose technologies show up years later in its products, Reuters noted. In 2013, Apple acquired small Israeli company PrimeSense that made three-dimensional sensors. The iPhone X, launched last year, used a similar sensor to power facial recognition features.

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5. -- Tesla's Head of Human Resources Is on Leave

Tesla Inc.'s (TSLA) head of human resources and facilities, Gabrielle Toledano, has been on a leave of absence as the electric vehicle company has gone on a wild ride recently spurred by CEO Elon Musk, who said earlier this month saying he was considering taking the company private, Bloomberg reported. Musk abandoned those efforts last week.

Toledano joined Tesla as chief people officer in May 2017 from Electronic Arts Inc. Toledano confirmed to Bloomberg she was on leave when reached by phone Wednesday but declined to comment further. A Tesla spokesman said the leave was prompted by Toledano's request and her duties were being handled by other members of the HR team.

Toledano, 51 year old, is one of Tesla's highest-ranking women. She reports directly to Musk.

Several senior executives have taken extended leaves of absences from Tesla in recent years, Bloomberg noted.