Updated to include details of KKR's deal to acquire WebMD.
 
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Here are five things you must know for Monday, July 24:
 
1. -- U.S. stock futures were declining Monday, July 24, after the International Monetary Fund lowered U.S. growth forecasts and as investors prepared for the busiest week of the second-quarter earnings and the two-day Federal Reserve meeting that begins on Tuesday, July 25.
 
Asian stocks ended Monday's session mixed. Japan's Nikkei 225 index fell 0.6%, while the Shanghai Composite rose 0.4%. Stocks in Europe fell.
 
Oil prices in the U.S. early Monday were up 0.76% to $46.12 a barrel ahead of an OPEC meeting in Moscow that was expected to discuss further production limits but was unlikely to seek to cap growing output from Nigeria and Libya.
 
Economists don't expect the Federal Reserve to make any changes to interest rates when the meeting concludes in the afternoon on Wednesday, July 26. The Fed raised its key interest rate for the third time in six months when the central bank last met in June.
 
The economic calendar in the U.S. on Monday includes the PMI Composite Flash for July at 9:45 a.m. ET and Existing Home Sales for June at 10 a.m.
 
2. --  The International Monetary Fund lowered growth forecasts for the U.S. economy on Monday amid expectations of a pullback in government stimulus.

The IMF said it expects the U.S. economy to grow at a 2.1% clip this year and next, down from its prediction of 2.3% and 2.5%, respectively, that it published three months ago in its regular World Economic Outlook report.

"While the markdown in the 2017 forecast reflects in part the weak growth outturn in the first quarter of the year, the major factor behind the growth revision, especially for 2018, is the assumption that fiscal policy will be less expansionary than previously assumed, given the uncertainty about the timing and nature of U.S. fiscal policy changes," the IMF said. "Market expectations of fiscal stimulus have also receded."

The growth forecast for the U.K. in 2017 also was revised lower on weaker-than-expected activity in the first quarter.

3. -- Earnings reports are expected Monday from Alphabet Inc. ( GOOGL - Get Report)  and Arconic Inc. ( ARNC - Get Report) .
 
Alphabet and Arconic are holdings in Jim Cramer's Action Alerts PLUS Charitable Trust Portfolio. Want to be alerted before Cramer buys or sells GOOGL or ARNC? Learn more now .
 
Stanley Black & Decker Inc. ( SWK - Get Report)  reported second-quarter adjusted earnings on Monday of $2.01 a share and raised its earnings forecast for 2017. 
 
Halliburton ( HAL - Get Report) posted second-quarter adjusted profit of 23 cents a share, beating analysts' estimates by 5 cents. Revenue of $4.96 billion came in below forecasts.
 

 
4. -- Private-equity firm KKR & Co. ( KKR - Get Report)  agreed to acquire online health publisher WebMD Health Corp. ( WBMD)  in a deal valued at $2.8 billion.
 
Reuters had reported earlier that a deal could be announced Monday.
 
The purchase price is $66.50 a share in cash. WebMD shares closed Friday at $55.19.

The deal came after WebMD ran a five-month auction and solicited bids from more than 100 companies and private-equity firms, the people told Reuters. 

WebMD's websites include WebMD.com, Medscape.com and MedicineNet.com.

5. -- Jordan Spieth battled tough conditions, his swing and a surging Matt Kuchar on Sunday to win the Open Championship at Royal Birkdale Golf Club.

The win gives the the 23-year-old Spieth his third major championship. He now joins Jack Nicklaus as among the only golfers to win three parts of golf's Grand Slam before turning 24 years old.

Spieth netted $1.8 million for the win, bringing his career winnings on tour to $33 million.