Belgian brewer Anheuser-Busch InBev agreed to buy U.K.-based SABMiller for $100 billion-plus, but the deal could be held up over fears of job losses and tax-base erosion in South Africa, Reuters reports in Euronews.

Founded in 1895, South African Breweries was the first industrial company to list on the Johannesburg Stock Exchange. SABMiller moved its headquarters and primary stock market listing from Johannesburg to London in 1999, but the company retains a South African flavor, Reuters reports.

SABMiller operates in 80 countries but in South Africa, it still employs about 8,800 people — almost 13 percent of its total. It contributed around $1.2 billion to tax revenue in the 2014-2015 fiscal year.

Four SABMiller board members including its chairman and CEO are South African. Its 10-member executive committee includes seven South Africans.

AB InBev’s reputation for cutting costs has alarmed South African unions, Reuters reported.

“SABMiller was built on the back and by the hard work of the South African workers and they deserve to be heard and given assurances with respect to the security of their jobs,” said Congress of South African Unions (Cosatu) spokesman Sizwe Pamla.

During apartheid, SAB thrived in South Africa with a near-monopoly on the beer market and interests in hotels, supermarkets, bars and furniture, according to Reuters.

When sanctions were lifted in 1990, SABMiller began expanding with an international shopping spree in Europe, China and elsewhere in Africa. Buying brands like Peroni, Miller, Pilsner Urquell and Grolsch, it became the world’s second-largest brewer.

AB In Bev is No. 1.

The South African government has a track record of delaying deals while imposing strict conditions to prevent job losses, according to Reuters. South Africa has a 25 percent unemployment rate.

In a worst-case scenario, the South African government could try and block the deal if it leads to a tax base erosion, said Lungisa Fuzile, director general at the National Treasury, in a Reuters interview.

Since a combined ABInBev-SABMiller deal would potentially control nearly a third of global beer sales, antitrust regulators in Europe and the U.S. will also give the merger a hard look, NewYorkTimes reported.

If the deal goes through with SABMiller, ABInBev said its headquarters would remain in Belgium, where the company acknowledges it gets tax advantages. Belgium’s official corporate tax rate is 34 percent, but ABInBev paid a fraction of 1 percent on the profit of $1.93 billion it reported in 2014 in Belgium, NYTimes reports.

In South Africa, anti-trust authorities are mandated to safeguard jobs, according to Reuters.

The Congress of South African Unions – part of the governing alliance with the ruling African National Congress – has urged the government not to ratify the SABMiller-ABInBev deal.

“It’s highly likely the Competition Commission is certainly going to look over the deal with a fine-tooth comb for any signs of job losses,” said Nic Norman-Smith, a fund manager at Lentus Asset Management, in a Reuters interview.

ABInBev acknowledged, in a statement, that its “corporate tax payments in Belgium have been low in recent years,” but said it had complied “with all tax legislation, both in our home country Belgium and in all other countries where we do business,” NYTimes reported.

There’s no precedent for South Africa blocking deals over concerns about tax erosion but it has blocked cross-border deals, according to Reuters. In 2009, it thwarted a deal between telecoms companies MTN Group and Bharti Airtel, citing concern MTN could lose its national character.

In 2011, U.S. company Walmart was told not to cut jobs for two years following its acquisition of retailer Massmart. The concessions delayed the $2.4 billion deal by at least two months.

Miner Glencore’s acquisition of Xstrata was delayed two months over delays in South Africa, where unions pushed for job preservation.