NEW YORK (TheStreet) -- Stocks erased an earlier rally by mid-morning Monday, dipping into the red as investors digested a range of data from the ISM Manufacturing Index to U.S. personal income.

The S&P 500 was down 0.15%, the Dow Jones Industrial Average fell 0.09%, and the Nasdaq slid 0.33%.

Intel (INTC) - Get Intel Corporation (INTC) Report reached a deal to buy Altera (ALTR) - Get Altair Engineering Inc. Class A Report for $54 a share, or $16.7 billion in cash. Intel fell 1.7%, while Altera climbed 6.1%. Click here for more.

The ISM Manufacturing Index increased to 52.8 in May from 51.5 in April, above estimates of 51.8. That marked its highest level since February. Separately, construction spending increased 2.2% compared to an expected 0.7% gain. 

"This was a very strong ISM manufacturing sector report, and it comes at a time when doubts about the rebound in economic growth momentum are beginning to surface," said Millan Mulraine, U.S. strategist at TD Securities. "For the [Federal Reserve], this report should do little to change the dynamics at the next meeting later this month, and we continue to see September as the earliest possible time for the Fed to get the necessary confirmation in the recovery to justify raising rates."

Boston FedPresident Eric Rosengren isn't so confident in a rate hike sooner than later. Sluggish growth since winter means the conditions for a rate hike have not been met, he said in a speech on Monday. Rosengren is a non-voting central bank member this year.

"The data were not just weak during the worst of winter; they were also weak before the storms and have been weaker than expected ever since," Rosengren told a business group in Hartford, Conn. "This, in my view, makes a compelling argument for continued patience in monetary policy."

U.S. personal income in April increased 0.4% after a flat reading a month earlier. Economists had expected the measure to tick up 0.3%. Personal spending remained flat, as expected, after a revised 0.5% increase in March.

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"The April income and spending figures are another reminder that even though their incomes are rising at a healthy pace, households are still reluctant to boost spending more freely," said Paul Ashworth, chief U.S. economist at Capital Economics.

The focus this week will be on economic data, culminating in Friday's closely watched jobs numbers. Economists hope to see continued strength in the labor market, proof that March's disappointing number was an aberration in a weak first quarter.

Expectations are for the U.S. to have added 210,000 jobs in May with the unemployment rate remaining unchanged at 5.4%. Hourly earnings are forecast to increase 0.2% month on month.

Aside from Friday's jobs report, April factory orders will be released Tuesday, and the trade balance for April will be released Wednesday. The Fed's Beige Book, an anecdotal report of the 12 Federal Reserve districts, will be released on Wednesday afternoon.

OM Group (OMG) rocketed 27.6% higher after funds managed by affiliates of Apollo Group (APO) - Get Apollo Global Management Inc. Class A Report agreed to purchase the specialty chemicals developer for $34 a share, 28% higher than Friday's close. Apollo plans to spin off OM's electronic chemicals and photomasks units to Platform Specialty Products (PAH) - Get Element Solutions, Inc. Report for $365 million in cash. 

Citigroup (C) - Get Citigroup Inc. Report shares were on watch on reports the bank could close its Banamex USA unit after federal authorities announced an investigation into possible money laundering violations. Regulators reportedly want the unit to pay more than $100 million to settle allegations, according to Reuters.

Four clinical trials involving the checkpoint inhibitors from Merck (MRK) - Get Merck & Co., Inc. (MRK) Report and Bristol-Myers Squibb (BMY) - Get Bristol-Myers Squibb Company Report showed promising signs of efficacy in a wide range of solid tumors. Bristol-Myers shares were 3.3% higher. Click here for more.

Lumber Liquidators (LL) - Get Lumber Liquidators Holdings, Inc. Report shares were on watch after the company responded to inquiries as to why it relabeled certain engineered hardwood flooring products. The company said it did so because a supplier mislabeled some California Air Resources Board compliance numbers on some products, though said they remained CARB Phase II compliant. 

Stocks closed Friday's session lower after a downward first-quarter GDP revision pressured markets. Benchmark indexes, however, notched a gain for May. Click here for more.