10 things you need to know before the opening bell

Here is what you need to know.

Chinese stocks saw another day of selling. The Shanghai Composite fell 1.3% amid a volatile session. Chinese stocks opened up to solid gains before tumbling to a loss of more than 4%. Then stocks raced into positive territory amid suspicions of intervention by the Chinese government, but those gains were short-lived and stocks slid into the close. The Shanghai Composite is down 43% from its June 12 high.

Markets around the world trade mixed. Japan's Nikkei (+3.2%) outperformed in Asia and Britain's FTSE (-1.1%) leads the way lower in Europe. S&P 500 futures are higher by 33.25 points at 1906.00.

Schlumberger is buying Cameron. The world's largest oilfield services company is buying oilfield equipment maker Cameron for $14.8 billion. Reuters reports, Cameron shareholders will receive $66.36 - $14.44 in cash and 0.716 of a Schlumberger share - per share. The price tag represents a 56.3% premium to Tuesday's closing price.

Transocean wants to stop its dividend. The offshore oil driller is seeking shareholder approval to cancel its third and fourth quarter dividend payments. The Wall Street Journal reports, the company announced back in February it was reducing its quarterly payout by 80% to $0.15 per share as a result of it being part of a "cyclical and capital-intensive industry." The company saw second quarter revenue fall 19% compared to last year as a result of the oil crash.

Oshkosh scored a big army contract. The US Army has awarded Oshkosh an eight-year armored truck contract worth up to $30 billion. According to the Journal Sentinel, the initial contract is for the purchase of 17,000 multipurpose vehicles at a price tag of $6.75 billion, but could reach as much as 50,000 vehicles. Also, the US Marine Corps will buy up to 5,500 vehicles as part of the deal. In addition, the contract could bring years of parts and service repairs, reports the Journal Sentinel. The first vehicle is scheduled to be delivered in 2017.

A utilities merger has been blocked. Exelon Corp's $6.8 billion buyout of Pepco Holdings has been blocked by regulators, according to Reuters. The three-member D.C. Public Service Commission decided the companies have not yet shown how the deal is in the best interest of the public. The companies have 30 days to ask the commission to reconsider.

Cnooc's profit plunged. The state-owned Chinese oil giant saw its first half profit plunge 56% versus a year ago to RMB 14.7 billion ($2.3 billion). Revenue tumbled 35.5% to RMB 89.59 billion. "In the first half of 2015, the Company made tremendous efforts to reduce costs and enhance efficiency. As a result of these initiatives, our exploration, development and production activities have maintained stable growth, and major financial indicators remained healthy," CEO Li Fanrong said.

The market volatility is exactly why the Fed needs to hike in September. At least that's what Brean Capital's Peter Tchir thinks. According to the Tchir, not hiking rates will send the markets the wrong message. He says, "If the economy deteriorates after the hike, they will cut. Or they will do QE4. I still bet that we see QE4 before 1.00% of Fed Funds, but I think the right move is to hike in September."

US economic data is light. Durable orders will cross the wires at 8:30 a.m. ET and crude oil inventories are due out at 10:30 a.m. ET.Treasury will auction $35 billion 5-year notes at 1 p.m. ET. The US 10-year yield is up 3 basis points at 2.10%.

Earnings reports flow. Abercrombie & Fitch, Express and Royal Bank of Canada highlight the names reporting ahead of the opening bell. Avago Tech, PVH and Williams-Sonoma are the notables releasing their quarterly results after the close.