China's Didi taxi app set to be most valuable Asian start-up

China's ride-hailing leader Didi Chuxing is close to finalising a fund-raising deal that would make it the most valuable start-up in Asia with a value of $50 billion.

Didi, founded in 2012, claims nearly 90 percent of China's ride-hailing market after buying rival Uber's assets in the country last year.

The $50 billion valuation would make Beijing-based Didi the most valuable startup in Asia and number two in the world after Uber's $68 billion, according to rankings by The Wall Street Journal.

It would move Didi past Chinese smartphone maker Xiaomi, which is currently second at 46 billion.

The Wall Street Journal's rankings were based on companies "that are privately held, have raised money in the past four years and have at least one venture-capital firm as an investor."

Didi, which completes 20 million rides daily, has sought to expand overseas with an investment into Southeast Asian taxi-booking app Grab last year, following closely on the heels of a tie-up with Uber's US rival Lyft.