Every big bank in town wanted a piece of the Alibaba Group Holding Ltd initial public offering, set to be the biggest technology listing ever.

So much so that, according to Thomson Reuters data, major banks skipped an estimated $100 million in combined fees they could have made from work for other clients over the past year.

People familiar with the matter say that's because the banks didn't want to irk the Chinese e-commerce giant by working for its rivals or acquisition targets, and risk losing out on business in an IPO expected to be bigger than Facebook Inc's $16 billion listing in 2012.

Alibaba's giant IPO comes amid a wave of deals in China's tech sector, putting banks in a tricky situation when it comes to backing clients in the industry. In a sector that's red-hot, companies are sensitive about letting advisors work on deals that run parallel to those of competitors for fear of confidential information leaking out.

Another concern for companies is that a financial advisor already supporting one IPO in the space can't give its undivided attention to a rival's deal. As the major investment banks operating in the region remained on standby over the past year for Alibaba's IPO, they kept their distance from the giant's peers in hopes of winning a role on the mega-deal, the people familiar with the matter said.

An estimated $300 million in fees are up for grabs in a listing that Alibaba said on March 16 will take place in the United States. Tuesday marked the first meeting of the bankers, lawyers and accountants helping the company on the deal, getting together in Hong Kong, which houses part of Alibaba's corporate finance team.

Citigroup, Credit Suisse, Deutsche Bank, Goldman Sachs, JP Morgan and Morgan Stanley are the banks working on the IPO, Reuters previously reported.

All six banks are existing lenders to Alibaba, putting them in good position to win the coveted mandates, the people familiar with the matter said. The estimated fees from Alibaba's IPO would make it the biggest Chinese fee payer to global investment banks in a decade.

"Because Alibaba is a very big transaction, people are very keen, the process is so competitive," said Ronald Wan, chief China advisor at financial services firm Asian Capital Holdings. "So you have the view that if you're not a friend, you're an enemy. And there's nothing in between," Chan said.

A Hong Kong-based spokeswoman for Alibaba declined to comment.

Banks mentioned in the story either declined to comment or did not respond to emails seeking response. Sources declined to be identified as they were not authorized to speak to the media.

BATTLE LINES

A recent unsolicited bid by Alibaba to buy out a Chinese internet company exposed the battle lines. Alibaba, which already owns 28 percent of digital mapping company AutoNavi Holdings Ltd, last month offered to buy the rest of the company in a deal valuing the target at $1.6 billion.

When AutoNavi tapped advisors to organize its defense, some investment banks passed on the business to avoid potential conflicts with the mega-IPO, people familiar with the matter said. In the end, AutoNavi's independent committee hired Lazard Ltd as its financial advisor. AutoNavi declined to comment for this article.

Banks usually pounce on defense mandates like this. These are lucrative roles for mergers and acquisitions departments which can command a fee of nearly 2 percent of the total deal value.

In February 2012, well before Alibaba launched its IPO process, IFR reported that at least five banks, including Credit Suisse, Goldman Sachs and Morgan Stanley, were in the running for mandates to underwrite an IPO by JD.com, the number two e-commerce company in China. When the Alibaba competitor filed for a $1.5 billion U.S. IPO last month, only two underwriters were in: Bank of America and UBS.

An external spokesman for JD.com declined to comment saying the company was in a quiet period ahead of its IPO.

Similarly, when Tencent Holdings, Alibaba's biggest Chinese Internet rival, and JD.com announced a tie-up this month, all of the six banks working with Alibaba were out of the picture, people familiar with the matter told Reuters. Instead, Tencent was advised by Barclays, while Bank of America was JD.com's financial adviser.

Tencent did not reply to emails or phone calls seeking comment.

In Alibaba's $804 million friendly bid this month to buy a controlling stake in ChinaVision Media Group Ltd, mainstream banks again didn't sign up with the target company. While Goldman Sachs advised Alibaba, little-known Reorient Financial Markets Ltd was the financial adviser for ChinaVision.

ChinaVision did not reply to email seeking response.

"You can see how banks have used their calculators to figure out how big this deal could be," said Wan, of Asian Capital Holdings. "And so they'll try not to do anything to upset Alibaba or its management."