Investors rush for a slice of Didi's U.S. IPO

Investors have rushed to place bids for the upcoming IPO by Chinese ride-hailing giant Didi.

Reuters sources say all the available shares were snapped up within a day.

That puts the firm on track to raise around $4 billion.

If confirmed, that would make it the biggest U.S. share sale by a Chinese firm since Alibaba raised $25 billion in 2014.

It would also very likely be the biggest U.S. IPO this year.

The figures suggest a valuation for Didi of up to $67.2 billion.

A big number, but actually down on earlier estimates of up to $100 billion.

Investors have grown concerned over China's crackdown on its tech titans.

Last week Reuters reported that the country's market regulator had opened a probe into Didi.

It's looking at whether the firm unfairly squeezed out smaller rivals.

Some market-watchers also wonder about the firm's rapid growth rate.

One prospective investor told Reuters that would be hard to maintain, given Didi's high market share in big cities, and the growing competition in smaller towns.

But this week's rush for shares suggests plenty still want a piece of the action.

Didi shares should start trading on Wednesday (June 30) after a short roadshow for investors.