Alibaba valued at up to $250 billion in grey market bids

The hype surrounding the float of Chinese e-commerce giant Alibaba climbed one notch higher on Thursday, with one London-based spread better revealing expectations of an initial valuation reaching as much as $250 billion.

A "grey market" for its shares has sprung up after the company announced on Sunday that it had decided to begin the process of an initial public offering (IPO) in the United States, ending months of speculation. This unofficial pre-market enables traders to place bets as to what level its market capitalization will close at after the first day of official trading.

London-based spread better IG Markets told CNBC that the highest bid it had received for Alibaba's valuation had been $250 billion. It had received no sell orders. "It's IPO central around here at the moment," Brenda Kelly, a market strategist at the company told CNBC via telephone. A figure of that magnitude would mean Alibaba would emerge as the world's tenth-biggest company by market value, according to Reuters data.

(Read more: With Alibaba IPO official, pressure mounts on Yahoo)

Kelly added that the heightened interest had been garnered by the previous listings of Facebook and Twitter, but said that its growth possibilities meant it could receive a lot more attention. "This is the grand daddy of them all, I reckon," she said.

Alibaba headquarters in Hangzhou, China.
ChinaFotoPress | Getty Images

Alibaba, the e-commerce platform set up in 1999 by billionaire Jack Ma, is expected to use Twitter's November IPO as a barometer of investor appetite for technology shares. It comes as talk of a bubble in the tech sector resurfaces.

(Read more: E-commerce giant Alibaba starts plan for US IPO)

Twitter's sizzling debut raised around $2.1 billion and the firm ended its first day with a market capitalization of about $25 billion. This made it larger than more than half the companies in the S&P 500. On Facebook's debut it sold 421.2 million shares to raise $16 billion, giving it a $104.2 billion market value.

Expectations have been building for months, with bankers predicting an IPO that could raise up to $15 billion for Alibaba and value the company at more than $100 billion. A Reuters survey this week sees traders having a more optimistic view, with an average from 12 brokers giving an expected value of $141 billion.

Will Alibaba shun Nasdaq for the NYSE?
Will Alibaba shun Nasdaq for the NYSE?

(Read more: Alibaba's ditch - How bad is it for Hong Kong exchange?)

Alibaba serves millions of buyers and suppliers from more than 240 countries and regions, it says on its website, and is classed as a new technology heavyweight that could rival Amazon. On Thursday, messaging app Tango announced Alibaba had invested $215 million in the group. This gives the Chinese company a minority stake in a messaging service with over 200 million registered users and over 70 million active users.

Garvis Toler, head of equity capital markets at Dealogic said that the size of Alibaba's IPO would be "major" and would give underwriting fees of roughly $400 million to the banks involved. "(This) is the fourth largest on record for a U.S.-listed IPO," he told CNBC, regarding the underwriting fees.

By's Matt Clinch. Follow him on Twitter @mattclinch81.