 Bloomberg -- Goldman Sachs Group Inc. and Bank of America Corp. were left off Ant Groups upcoming stock sale in Hong Kong because of their past work with rivals of its affiliate Alibaba, according to people familiar with the matter.Bankers have been told by senior executives at Alibaba Group Holding Ltd., which owns a third of Ant, that they should refrain from doing deals for its competitors if they want business from Jack Mas sprawling empire, the people said. Ant has kicked off plans to go public in Hong Kong and Shanghai in offerings that could top Saudi Aramcos record 29 billion IPO.The directive shows that Wall Street banks are having to make early bets on which firms to stick with in China, especially as juggernauts like Alibaba and Tencent Holdings Ltd. extend their tentacles into hundreds of businesses in finance, transportation, retail and entertainment.The duopoly issue is not unique to China, but the scale and scope of Alibaba and Tencents business operations create an excruciating dilemma for investment banks, said Andy Mok, a senior research fellow at the Center for China and Globalization in Beijing. Alibaba and Tencents businesses are so big, you can risk being blocked out of a significant future revenue stream.While bankers everywhere have to be careful doing work for their clients rival firms, Chinese conglomerates are taking it to a new level. Even though banks have firewalls to ensure separate teams handle deals for the likes of Alibaba and Tencent, thats proving to not be enough, the people familiar said.Chinese clients are much more likely than their counterparts in the U.S. or Europe to demand non-compete commitments as a show of loyalty, and to ensure that sensitive strategies dont land in the hands of competitors. And with fewer deals to go around, bankers in the hyper-competitive Chinese market have little choice but to comply.Though minor distribution roles on Ants Hong Kong IPO are still up for grabs, those dont offer the out-sized fees that banks can expect from leading the sale.Competition has increased and Chinese issuers have gotten strong bargaining power, said Bob Dodds, who worked as an investment banker at China International Capital Corp. before setting up DRP Capital Ltd. to advise on China-related deals.Goldman and Bank of Americas recent work with Alibaba rivals include 7.7 billion in stock sales for Tencent-backed Pinduoduo Inc. and JD.com Inc. in the last two years, helping these companies build their war chests to take on their larger competitor in the hotly contested e-commerce arena.The two banks have reaped at least 70 million from advising Pinduoduo and JD.com on stock deals, according to data compiled by Bloomberg. The figure doesnt include the undisclosed fees of a 1 billion bond sale by Pinduoduo in September and the 4.5 billion secondary listing by JD.com in June.Representatives at Goldman and Bank of America declined to comment. Ant and Alibaba declined to comment in separate emailed statements.IPO BankersAnt is aggressively competing with Tencents WeChat Pay to maintain its dominance of Chinas 29 trillion mobile payments space. It has been pitching digital payment services to the local arms of KFC Holding Co. and Marriott International Inc. as it transforms its Alipay app into an online mall for everything from loans and travel services to food delivery.Alipays share of mobile payments has increased for three consecutive quarters, rising to 55.1 in the fourth quarter, according to consultant iResearch. Tencent has 38.9 of the market.Ant hired Citigroup Inc., JPMorgan Chase Co., Morgan Stanley and CICC to lead its Hong Kong IPO. The sale is expected to raise more than 10 billion and could value the firm at 200 billion, people familiar have said. Ant hasnt selected banks for the Shanghai portion, though global firms will probably be left out because lead underwriters for any IPO on the tech-focused Star board must buy shares in the deal.Banks leading the Ant IPO in Hong Kong have fewer conflicts. While Morgan Stanley earned 6.4 million for a junior role in Pinduoduos stock sale last year -- about half of Goldmans haul -- Citigroup and JPMorgan werent involved in those deals, Bloomberg data shows.Adds details on Alipay and WeChat Pays market share in 13th paragraph. An earlier version of the story was corrected to show Ant has kicked off its IPO process.For more articles like this, please visit us at bloomberg.comSubscribe now to stay ahead with the most trusted business news source.2020 Bloomberg L.P. 