The little known biggest web retailer

Alibaba, the world's largest internet retailer, is set to float on the US stock market, in an initial public offering that could raise around $20bn and see it valued at up to $170bn.

The technology journalist Rupert Goodwins told Today programme business presenter Justin Rowlatt that the China-based company "is doing very, very well" and is going to end up as big as Amazon "and ready to take Amazon on".

First broadcast on BBC Radio 4's Today programme on Tuesday 9 September.