Market Update: S&P 500 and Nasdaq Close at Flatline, Dow Adds About 45 Points

Stocks reversed their earlier increase and ended mostly at a flatline on Tuesday as a downturn in technology shares pulled the S&P 500 and Nasdaq lower, while the Dow Jones Industrial Average ticked modestly higher. Cyclical sectors like Energy (NYSE: XLE), Materials (NYSE: XLB) and Financials (NYSE: XLF) continue to outperform the broader market, while Health Care (NYSE: XLV), Utilities (NYSE: XLU) and Information Technology (NYSE: XLK) dragged lower.

Investors were encouraged by positive U.S. coronavirus pandemic trends, with decreases seen in infection, hospitalisation and death rates as more of the nation's population gets vaccinated. Currently, more than half of the U.S. population has received at least one dose of either a Pfizer (NYSE: PFE)-BioNTech (NASDAQ: BNTX), Moderna (NASDAQ: MRNA) or Johnson & Johnson (NYSE: JNJ) COVID vaccine, according to U.S. Centers for Disease Control and Prevention data.

Here's how the market settled on Tuesday:

S&P 500 Index (NYSE: SPY): -0.05% or -2.04 points to 4,202.07

Dow Jones Industrial Average (NYSE: DIA): +0.13% or +46.25 points to 34,575.70

Nasdaq Composite Index (NASDAQ: QQQ): -0.09% or -12.26 points to 13,736.48

World's largest meatpacker pauses operations after weekend cyberattack:

JBS, the world's largest meatpacker, announced on Tuesday that it has canceled shifts at large U.S. and Canadian meat plants after the company experienced a cyberattack over the weekend. This pause in production threatens to disrupt food supply chains and inflate food prices.

"On Sunday, May 30, JBS USA determined that it was the target of an organised cybersecurity attack, affecting some of the servers supporting its North American and Australian IT systems," the company said in a Monday statement.

The cyberattack also caused JBS's Australian operations to shut down on Monday. The company is working to resolve the incident and restart operations as soon as possible.

Here's how the market stands in afternoon trade:

S&P 500 Index (NYSE: SPY): -0.14% or -6.02 points to 4,198.09

Dow Jones Industrial Average (NYSE: DIA): +0.07% or +24.80 points to 34,554.25

Nasdaq Composite Index (NASDAQ: QQQ): -0.14% or -19.89 points to 13,728.85

Manufacturing sector expanded more-than-expected in May:

U.S. manufacturing sector activity rose by a more-than-expected rate in May, as demand continues to increase as the economy reopens.

The Institute for Supply Management's Purchasing Managers' Index reading for May climbed to 61.2 from 60.7 in April, increasing at the fastest rate since March. May's rate exceeded consensus economist estimates for an increase to 61.0, according to Bloomberg. Readings above the neutral level of 50 indicated sector expansion.

Here's how markets started trading after opening bell:

S&P 500 Index: +0.70% or +29.36 points to 4,233.47

Dow Jones Industrial Average: +0.90% or +311.68 points to 34,841.13

Nasdaq Composite Index: +0.54% or +73.63 points to 13,825.46