San Francisco, London, Tokyo: Masayoshi Son is asking Wall Street banks to open their pocketbooks if they want in on what could be the biggest-ever initial public offering.

SoftBank Group Corp has told potential underwriters seeking a large role in the blockbuster IPO of its Japanese wireless unit that they should offer to lend to other parts of the parent company’s empire, according to people familiar with the matte. One option being discussed is banks lending a combined $8 billion (Dh29.38 billion), with SoftBank’s stake in British computer-chip designer ARM Holdings Plc being used as collateral.

Loans against stakes in other companies have also been considered as the group dangles the carrot of participating in the IPO of SoftBank Mobile. Firms offering financing are seen as much likelier to get a spot on the IPO.

“There is no truth to this,” SoftBank Spokesman Takeaki Nukii said by phone, declining to comment further.

Shares of SoftBank has gained 11 per cent this year compared with a 7.3 per cent drop in the Topix index.

No final decisions have been made about the structure of the loans or their collateral and SoftBank could still decide to give roles to non-lending banks as well. Some of the discussions have also included the idea of lending to SoftBank’s almost $100 billion Vision Fund, some of the people said.

At stake for the world’s biggest banks are the fees and prestige from participating in potentially the biggest-ever global listing. SoftBank is talking to advisers about selling a one-third stake in SoftBank Mobile in a listing valuing the company at $90 billion.

Son said in an investor presentation last month that he’s working toward a listing on the Tokyo Stock Exchange for SoftBank Mobile. IPO-bound companies and their backers typically give preference to banks that they have worked with on deals or used as a customer.

Take Snap Inc. The disappearing photo app maker placed a big consideration on which firms had loaned it money when choosing underwriters, people familiar with the matter said at the time. Bank of America Corp declined to lend to the money-losing company and ultimately didn’t have a role on its listing.

The situation with SoftBank Mobile is unique, though. That’s because some firms have been asked to lend to a different part of the conglomerate than the company that’s actually listing.

Banks are evaluating whether the lending being discussed is possible. Such deals would have to clear a risk assessment at large firms, they said.