Goldman Sachs Group Inc. and Bank of America Corp. were left off Ant Group's upcoming IPO in Hong Kong due to past working relationships with rivals of Alibaba, Ant's affiliate.

Both companies were told by senior executives atAlibaba Group Holding Ltd., which owns a third of Ant, to refrain from doing business with competitors if they want to do business with Ant, according to a Yahoo Finance report. The plans for Ant to go public in Hong Kong and Shanghai could top Saudi Aramco's record of a $29 billion IPO.

The Chinese conglomerate has demanded non-compete orders to ensure business strategies are kept secret and also, as a sign of loyalty, according to the report.

Goldman and Bank of America's recent work with Alibaba rivals include $7.7 billion in stock sales for Tencent-backed Pinduoduo Inc. and JD.com Inc. and helping the companies take on larger competitors in the e-commerce arena.

Ant is aggressively competing with Tencent's WeChat Pay to maintain the $29 trillion mobile payments space. Alipay's 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. Ant hasn't selected banks for the Shanghai IPO, but the rumors are that global firms will probably be left out because lead underwriters for any IPO on the tech-focused board must buy shares in the deal.