In the tiny North Carolina town of Tar Heel, the Smithfield Foods Packing Co., the world’s biggest slaughterhouse that often smells of pig manure, belongs to a giant Chinese meat-processing company.

Hundreds of movie theaters across the country are owned by the Kansas City-based AMC Theatres chain, which reports to China’s richest man.

And in Miami, a luxury condo tower called One Thousand Museum is rising over Biscayne Bay. Its contractor is a Chinese firm, the largest builder in the world’s most populous country.

In a presidential campaign focused on the loss of American jobs, a recent study shows how U.S. jobs are created or preserved under China’s investment boom in the United States.

China has spent more than $100 billion since 2000, buying or making significant investments in 1,900 companies. That flow is accelerating: In the first quarter of this year, Chinese firms had $30 billion in pending or completed deals, according to Stephen Orlins, head of the National Committee on U.S.-China Relations, a New York-based organization that researches the two countries’ ties.

The Chinese purchasers, many of them state-owned or with close government ties in Beijing, are responsible for almost 100,000 American jobs, according to a recent report by Orlins’ organization and the Rhodium Group, a New York company that provides research on global business trends to U.S. and foreign companies.

One of those jobs is held by Brad Meltzer, president of Plaza Construction Florida, which is building One Thousand Museum, set to open by next spring with a $49 million penthouse and condos starting at $5.7 million.

The Miami-based company’s parent group, Plaza Construction, is headquartered in New York. It’s owned by China Construction America of Jersey City, N.J., a subsidiary of China State Construction Engineering LTD in Beijing. “That investment has offered us dynamic growth opportunities,” Meltzer told McClatchy.

Most purchases of American firms by Chinese or other foreign companies draw little, if any, attention from the U.S. government. But a small number raise such high national security concerns that they are vetted by a secretive multi-agency committee of six Cabinet secretaries and the U.S. attorney general.

The Committee on Foreign Investment in the United States (CFIUS), set up by President Gerald Ford in 1975 to safeguard the country, in recent years has focused increasingly on Chinese acquisitions.

Among the most high-profile deals, CFIUS in 2013 approved the Chinese purchase of Smithfield Foods, which has operations in 26 states and supplies ham and other pork products to the U.S. military.

Last year, it allowed the sale of the New York’s fabled Waldorf Astoria hotel, home to visiting American presidents and foreign dignitaries, to Anbang, one of China’s largest insurance companies.

However, CFIUS in 2012 rejected a Chinese firm’s purchase of an Oregon wind-farm complex because of its proximity to a major Navy training base. President Barack Obama upheld the decision after the Chinese company objected.

In February, 46 House Republicans led by Rep. Robert Pittenger of North Carolina wrote a letter asking CFIUS to conduct a “full and rigorous” review of the pending purchase of the Chicago Stock Exchange by Chongqing Casin Enterprise Group, a large Chinese real estate and infrastructure investment company. CFIUS is also expected to vet a $5.4 billion bid by Haier Group, which Scientific American named last year as one of China’s most innovative companies, to buy the appliance-division of General Electric, headquartered in Louisville, Ky.

“As China becomes more and more invested in the United States, it has a bigger and bigger stake in the success of the American economy, so that creates a shared interest,” said Chris Brewster, a Washington lawyer with Stroock & Stroock & Lavan who represents Chinese and other firms seeking to buy American companies. “At the same time, plainly these investments can present national security considerations for the United States.”

Chinese acquisitions now make up more than one-fifth of all foreign purchases or significant investments vetted by CFIUS. In 2013 and 2014, China moved ahead of all other countries for the first time, according to the committee’s required annual reports to Congress.

CFIUS is currently reviewing the pending purchase by China National Chemical Corp. of Syngenta. Although that’s a Swiss company, it has several key affiliates in the United States, starting with Syngenta Biotechnology Inc. in Research Triangle Park, N.C.

Because Syngenta is among the world’s biggest seed and pesticide companies, Sen. Marco Rubio, R-Fla., and other senators recently demanded that U.S. Agriculture Secretary Tom Vilsack participate in the national security review of its purchase by ChinaChem.

The agriculture chief is not by statute a CFIUS member, but Treasury Secretary Jack Lew, who chairs the panel, accepted the senators’ demand earlier this month.

“China’s proposed takeover of Syngenta is a serious issue impacting America’s food supply, and thus our national security as well as our public health,” Rubio said.

Thilo Hanemann, a Rhodium economist who heads the group’s research on global trade and investment, said the investment report was sorted by congressional district “because that also gave us an opportunity to inform members of Congress about this important new trend.

“The debate in Congress was in the past very much focused on potential risks and downsides from Chinese investment,” he said. “The potential upsides haven’t received as much attention, partially because there wasn’t any reliable data available.”

Hanemann said that American workers can see benefits as well. “Chinese companies are now coming to us, setting up facilities here and bringing jobs back to the United States that those workers have lost to China,” he said.

At the same time, he said, Chinese consumers benefit from ownership of Smithfield Foods, with more pork exports headed to China in the wake of a string of food-quality scandals there.

Even before the Chinese purchase of Syngenta, North Carolina’s fourth congressional district has the second-most Chinese investment – almost $3.4 billion since 2000 – in the country.

Lenovo, China’s largest personal-computing company, bought IBM’s personal-computing business based in Research Triangle Park in 2005. Two years ago, it completed the purchase of IBM’s x86 server business, also at RTP.

Lenovo now employs 5,000 people in North Carolina. Smithfield Foods and some 78 other Chinese-owned entities firms provide jobs for another 10,000 Tar Heel residents.

“In North Carolina’s Fourth District, we understand both the great benefits and potential pitfalls of increased participation in the global economy,”said Rep. David Price, a Chapel Hill Democrat. “Foreign investment can help create jobs and support domestic manufacturing, including innovative new facilities in the Research Triangle and throughout North Carolina.”

In Wichita, Kan., where Smithfield Foods employs 450 people at a large pork plant, Rep. Mike Pompeo takes a more cautious view.

“While there may be national security concerns with some foreign investors, including the Chinese, our government has a clear process in place to ensure the United States is protected,” the Wichita Republican said.

The subject of Chinese investment can be a sensitive one for lawmakers.

The Senate Leadership Fund, which backs Republican candidates and challengers, criticized Rep. Patrick Murphy, the Jupiter, Fla., Democrat seeking his party’s Senate nomination, for having met with a prominent Chinese businessman about investing in Florida.

Chinese investors are helping to finance the SkyRise Miami observation tower. Coastal Construction, owned by Murphy’s father, is one of two contractors, along with Meltzer’s Plaza Construction, that vies for the title of South Florida’s biggest builder.

“Is Murphy running to be Florida’s senator or China’s senator?” the Republican PAC taunted.

Rep. Kevin Yoder, an Overland Park, Kan., Republican, did not respond to multiple requests for comment on the $1.53 billion in Chinese investment in his district since 2000. That total was the 10th-highest among all 435 congressional districts.

Much of the investment in Yoder’s district came from the 2012 purchase of AMC Theatres by Wang Jianlin, a billionaire real-estate developer who is China’s richest man, and the subsequent construction in Leawood, a Kansas City suburb, of the movie chain’s national theater-support center.

House Appropriations Chairman Hal Rogers declined to comment when asked about the two Smithfield Foods slaughterhouses that provide 1,200 jobs in his Kentucky district.

Whether because of conditions imposed by CFIUS or by their own choice, most Chinese purchasers seem to maintain a largely hands-off approach to the American companies they buy.

Keira Lombardo, senior vice president of corporate affairs for Smithfield Foods, said Shuanghui International Holdings, now called WH Group, has not interfered since the giant Chinese meat processor paid $4.7 billion for the company in 2013. The hybrid company’s motto is: “The same old Smithfield, but better.”

In Miami, Meltzer describes only positive results in the two years since the Chinese construction behemoth bought his company. “Both sides agree that the acquisition has been a glowing success,” he said.