SINGAPORE - Singapore came in joint fourth in the world for how fast its start-ups turned into unicorns, according to a global ranking by British price comparison website Money.co.uk.

Singapore's six unicorns took an average of six years and 11 months to cross US$1 billion (S$1.35 billion) in valuation, according them that status. They include ride-hailing giant Grab and image recognition technology firm Trax.

China topped the ranking. Its 155 unicorns took an average of just five years and 10 months to reach the US$1 billion mark.

The second fastest economy for start-ups turning into unicorns is Hong Kong, where they took an average of six years and one month, followed by Japan with six years and three months.

Singapore shares the fourth spot for fastest time with the United States, which has 378 unicorn companies, and Australia, with six.

When it comes to producing the most unicorns, the US took the top spot, followed by China (155) and India (34).

Known for their rarity, there are currently only 750 unicorns in the world, Money.co.uk said, citing cbinsights.com.

The top-performing sector when it comes to time taken to reach a US$1 billion valuation was auto and transportation, whose 31 unicorns took an average of four years and five months.

Fintech produced the most unicorns with 131 such start-ups, followed by e-commerce and direct-to-consumer firms with 82.

Money.co.uk looked at privately owned companies valued at more than US$1 billion.

Countries with fewer than five start-ups were excluded from the study due to insufficient data to draw a relevant conclusion, the financial analytics and research firm said.