The potential $104.2 billion takeover of SABMiller Plc by Anheuser-Busch InBev could send ripples through the beer industry both domestically and worldwide. Those ripples could affect everyone from competitors like Heineken International to the surge of the craft beer segment that has threatened major brewers in recent years.

While major domestic beer brands in the U.S., such as light beer and others from AB InBev and MillerCoors, have seen their market share dip, craft beer has grown significantly in the past few decades. Craft claimed 11% of the U.S. beer volume market in 2014, with growth of 17.6%, as compared to the overall beer industry’s growth of 0.5%. The overall retail value of the U.S. beer market is $101.5 billion with craft making up $19.6 billion.

With that growth of craft beer has come diversity in the U.S. beer industry. However, that industry landscape could change if their merger goes through next year — leaving some in the craft beer segment concerned.

"Anything that threatens that diversity is definitely of a concern," said Julia Herz, craft beer program director at the Brewers Association. "This deal could negatively affect the progress that small brewers have made."

Distribution at the center of the debate

In a three-tier system with manufacturers, distributors, and retailers, distribution and access to market is of utmost importance in the beer industry, according to Herz. Many brewers can self-distribute or work with any one of the 3,300 independent distributors that exist in the U.S., according to a statement from AB InBev.

"The problem with distribution rights, at least in the U.S., is once sold, they can't be renegotiated or taken back. And if a distributor opts to downplay one beer (say, a craft brewer's product) in favor of another (for instance, an offering made by the macro company that owns the distributor), there's not much the smaller brewer can do about it," Fortune reported.

AB InBev acquired five distributors in three states over the past few months, including two in California, two in Colorado, and one in New York. This has prompted concerns from craft brewers, who allege that AB InBev "is seeking to curb competition in the beer market by buying distributors, making it harder for fast-growing craft brewers to get their products on store shelves," which the U.S. Justice Department is now investigating, according to Reuters' sources.

Craft brewers say that after AB InBev acquires distributors, they sometimes have more trouble distributing their beer, and sales growth slows or stops. Plus, with AB InBev moving to acquire more craft brewers, such as Golden Road Brewing and Elysian Brewing this year, AB InBev is poised to offer its craft beer selections that could crowd out independent craft brewers in terms of distributorship.

"Antitrust regulators are also reviewing craft brewers' claims that AB InBev pushes some independent distributors to only carry the company's products and end their ties with the craft industry, two of the sources said, noting that the investigation was in its early stages," Reuters reported.

MillerCoors recently announced its own first acquisition of a craft brewer, Saint Archer Brewing Co. However, it is widely believed that in this merger, AB InBev would have to divest the SABMiller's MillerCoors venture in the U.S. to pass through various regulatory hurdles. AB InBev had to do similar when acquiring Grupo Modelo in 2013, as the brewer had to sell some of Modelo's U.S. assets, including Corona.

Those distribution problems extend not just domestically, but internationally as well. Export volume for U.S. craft beer jumped 35.7% in 2014 to total nearly $100 million, according to Brewers Association.

However, "By dramatically expanding its existing distribution network in Europe, Asia, and other countries — and focusing on its own bigger brands as it has frequently done domestically — an AB InBev/SABMiller combo could hamper the expansion of U.S. craft beers in international territories," according to Fortune.

Herz recommends that craft brewers examine their relationship with distributor(s) in the wake of the potential merger.

"Where craft brewers are in the distribution game is key, and everybody is probably looking at who's distributing their brands and again how that distributor might evolve based on the acquisition," said Herz. "Craft brewers, just like any other alcohol sector within this big category of fermented beverages need to make sure … that they have good structured contacts that hopefully are mutually beneficial with those parties and that they have a relationship with a distributor that believes in their brands."

Other factors coming into play

Other factors of concern for craft brewers could be changes in pricing, access to raw materials, and competition for sponsorships, such as for sports stadiums, which could be controlled in part by a beer entity as large as a combined AB InBev-SABMiller, according to Herz.

Herz also raised the question about transparency in brand ownership and whether parent companies like AB InBev will disclose on beer product labels that they in fact own the brands they acquire. When a brand like Elysian is acquired by AB InBev, Elysian loses its status to call itself a craft brewer under the Brewers Association's definition, as it is more than 25% owned by an entity that is not a craft brewer. But whether that information will be readily disclosed to consumers remains unclear.

How the merger could benefit craft brewers

Not everyone in craft beer believes that such a major merger in the beer industry could be damaging to craft beer. Some say it could have hidden benefits.

"People take beer very personally," Brewers Association director Paul Gatza told Business Insider. "When something happens to their favorite beer or their ability to get it, or something helps or hurts a brewer they care about, they internalize it and want to do something about it. People may see [the merger] as a time to rally around their local brewery."

"The American public continues to respond [to big beer] by sampling more new craft brewed beers and buying more of their favorites. Those societal trends won't change because of this deal," Gatza wrote.

Founders Brewing co-founder and CEO Mike Stevens told Food Dive he believes the merger would give craft brewers room to grow in the U.S. while AB InBev shifts its focus elsewhere.

"As InBev puts more focus internationally it leaves the craft industry to continue growing its roots deeper into the U.S. market," he said.