Here are five things you must know for Wednesday, April 4:  

1. -- Dow Futures Plunge

U.S. stock futures plunged Wednesday, April 4, suggesting Wall Street would open with sharp losses after China said it would slap reciprocal 25% tariffs on 106 U.S. products including soybeans, cars, planes, whiskey, and chemicals.  

China's move was a response to the Trump administration's proposed tariffs on $50 billion in Chinese goods.

Contracts tied to the Dow Jones Industrial Average tumbled 446 points, while those linked to the broader S&P 500 fell 35.75 points. Futures for the Nasdaq were down 103.25 points.

The tariffs won't go into immediate effect with U.S. companies given until May 22 to raise objections.

Companies that could be hit by the tariffs on American goods were plunging in premarket trading. Boeing Co. (BA) - Get Report fell 4.7%, while General Motors Co. (GM) - Get Report was off 3.9%.

The sharp drop in U.S. stock futures threatened to wipe out stock market gains made Tuesday, April 3, when stocks closed higher. The Dow Jones Industrial Average gained 1.64% to close at 24,032 on Tuesday, the S&P 500 rose 1.26%, and the Nasdaq up 1.04%.

Watch TheStreet's newsroom discuss the key market moves below. 

2. -- ADP Reports Private Sector Jobs Gains

The private sector in the U.S. added 241,000 jobs in March, according to the ADP National Employment Report. Economists surveyed by FactSet had expected an increase of 205,000 jobs.

The ADP jobs report is a precursor to the official U.S. jobs report to be released on Friday, April 6.

The U.S. economic calendar on Wednesday also includes Factory Orders for February at 10 a.m. ET, and Oil Inventories for the week ended March 30, at 10:30 a.m.

Homebuilder Lennar Corp. (LEN) - Get Report   posted adjusted earnings in its fiscal first quarter of $1.11 a share, topping estimates, while revenue of $3 billion rose 28% from a year earlier. The stock gained 0.9% in premarket trading.

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3. -- Amazon Could Make Offer for India's Flipkart

Amazon.com Inc. (AMZN) - Get Reportmay make a rival offer to buy Indian e-commerce company Flipkart, which is in merger talks with Walmart Inc. (WMT) - Get Report , Reuters reported, citing local media.

Amazon held early exploratory talks to buy control of Flipkart but a deal with Walmart is more likely, daily newspaper Mint said on Wednesday, citing people with knowledge of the matter.

One person familiar with the matter told Reuters that the probability of a deal with Amazon was low, and that any such deal could spark monopoly concerns as Flipkart and Amazon dominate India's e-commerce market. 

Reuters reported in February that Walmart was in talks to purchase a stake of more than 40% in Flipkart. It would be one of Walmart's biggest overseas deals and comes as Amazon has committed to investing $5 billion in India as it expands aggressively, including into online grocery deliveries.

Amazon shares fell 2.5% in premarket trading on Wednesday.

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4. -- WPP Investigates CEO Sorrell Over Misconduct Claim

WPP PLC  (WPPGF)  on Wednesday said it had begun an independent investigation into CEO Sir Martin Sorrell, after reports of personal misconduct and inappropriate use of company funds.

American depositary receipts of WPP fell 2.1% in premarket trading on Wednesday.

The world's largest advertising group said its board appointed an independent counsel to conduct an investigation in response to an allegation of personal misconduct against Sorrell.

"The allegations do not involve amounts which are material to WPP," the company said.

The Wall Street Journal on Tuesday originally reported the investigation, with people familiar saying the board was looking into whether Sorrell misused company assets.

5. -- YouTube Shooting

The woman who shot three people Tuesday afternoon at YouTube's headquarters in San Bruno, Calif., was identified as Nasim Najafi Aghdam, 39 years old, of San Diego. Police said Aghdam believed she was being suppressed by YouTube and told her family members she "hated" the company.

Aghdam died of an apparent self-inflicted wound Tuesday after opening fire with a handgun at the video streaming company's headquarters, San Bruno police said in a statement. YouTube is owned by Alphabet Inc.  (GOOGL) - Get Report .

A law enforcement official with knowledge of the investigation told the Associated Press that Aghdam had a longstanding dispute with the company. The official said Aghdam used the name "Nasime Sabz" online. A website in that name decried YouTube's policies and said the company was trying to "suppress" content creators, the AP reported.

One of the victims - a 36-year-old man - was in critical condition, a spokesman for San Francisco General Hospital said. A 32-year-old woman was in serious condition and a 27-year-old woman in fair condition, the spokesman said.

(This article has been updated with fresh stock market prices).