Here are five things you must know for Tuesday, May 8:  

1. -- Stocks Lower as Markets Await Trump Decision on Iran

U.S. stock futures were lower Tuesday, May 8, as markets awaited a decision from Donald Trump on whether the U.S. will pull out of the Iran nuclear deal and renew sanctions on the oil-rich nation.

Contracts tied to the Dow Jones Industrial Average  fell 51 points, those linked to the broader S&P 500  declined 7 points, and Nasdaq futures were down 14 points.

It's widely expected the U.S. will pull out of the nuclear agreement with Iran. However, reports said Trump could hold off on re-imposing sanctions to increase pressure on European allies to strengthen the agreement. 

Global oil prices retreated from their three-and-a-half year peaks on Tuesday, as markets were clearly focused on Trump's decision, expected at 2 p.m. ET on Tuesday, on renewed Iran sanctions, a move that could take as much as 500,000 barrels of oil from the market each day. Oil traded in the U.S. fell 1.27% early Tuesday to $69.83 a barrel.

The U.S. economic calendar on Tuesday includes the Job Openings and Labor Turnover Survey for March at 10 a.m. ET.

Earnings reports are expected Tuesday from Walt Disney Co. (DIS) , Wendy's Co. (WEN) , Dean Foods Co. (DF) , Discovery Inc. (DISCA) , LendingClub Corp. (LC) ,  Marriott International Inc. (MAR)  and Occidental Petroleum Corp. (OXY) .

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2. -- Comcast Reportedly Is Preparing a Bid for Fox

Comcast Corp. (CMCSA) reportedly has explored financing for a bid to challenge Walt Disney's purchase of much of Twenty-First Century Fox Inc. (FOXA) .

Shares of Comcast fell 1.5% in after-hours trading on Monday, following a report from Reuters that said the Philadelphia media giant was preparing an all-cash offer. Fox was up 3.8% in premarket trading on Tuesday.
 
Comcast has asked investment banks to increase a bridge financing facility by as much as $60 billion so it can make an all-cash offer for the Fox assets, Reuters reported, citing sources.
 
Comcast CEO Brian Roberts only plans to proceed with the bid if a federal judge allows AT&T Inc.'s ( T) planned $85 billion acquisition of Time Warner Inc. ( TWX) to proceed, the sources said. The U.S. Department of Justice has opposed the AT&T-Time Warner deal over antitrust concerns, and a decision is expected in June. 

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3. -- Takeda Reaches Deal to Buy Shire for $62.4 Billion

Takeda Pharmaceutical Co. (TKPYY)  said Tuesday it reached an agreement to acquire Dublin-based drugmaker Shire PLC (SHPG) in a deal valued at $62.4 billion. 

Takeda said it has offered $30.33 in cash for each outstanding Shire share, as well as either 0.839 in new Takeda shares or 1.678 in existing Takeda American depositary shares. The deal values Shire at £49.01 per share, a 27.1% premium to the stock's closing price on Friday, May 4.

Shire shareholders will hold 50% of the combined company, which will be listed on the Tokyo Stock Exchange with ADSs placed on the New York Stock Exchange. 

"Since its inception, Takeda has transformed into an agile, R&D-driven global pharmaceutical company that is well-positioned to deliver innovative and transformative care to patients around the world," said Takeda CEO Christophe Weber. "Shire's highly complementary product portfolio and pipeline, as well as experienced employees, will accelerate our transformation for a stronger Takeda."

4. -- ValueAct Takes $1.2 Billion Stake in Citigroup

Activist investor ValueAct Capital Partners LP has built a roughly $1.2 billion stake in Citigroup Inc.  (C) , The Wall Street Journal reported.

ValueAct, which has built the position over the past four to five months, continues to boost it "opportunistically," according to a letter to its own investors reviewed by Journal.

The stake amounts to about 0.7% of Citigroup, which has a market value of $175 billion.

Citigroup shares rose 1.5% in premarket trading on Tuesday.

5. -- Elon Musk Expands His Stake in Tesla

Elon Musk, CEO of Tesla Inc. (TSLA) , purchased 33,000 shares of the electric carmaker, expanding his stake in the company.

The shares were bought at an average price of $298.50, according to a regulatory filing, which calculates out to be $9.85 million. 

Musk's stake in Tesla has increased to nearly 20%, according to Bloomberg.

Tesla was down 0.8% in premarket trading to $300.40.