An index measuring global yuan use reached a new high in April, with London's market share passing Singapore's for the first time since December 2011.

Standard Chartered said that the Standard Chartered Renminbi Globalisation Index reached a record high of 925 in April, up 3.7 percent from March.

The expanding pool of Dim Sum bonds and certificate of deposits was the biggest contributor to the increase, it said in a press release. "While slowing issuance momentum in May will likely weigh on our next index update, we expect bond issuance to rebound in June and July on the offshore bond issuance by the Chinese government, among other positive factors."

London has maintained its recent lead over Singapore in terms of cross-border payments, and its offshore yuan foreign exchange turnover has also been growing at a faster pace. "However, the recent launch of renminbi clearing services is set to boost Singapore's competitiveness," SC said.

Standard Chartered launched the index in November. The index covers the top three markets in offshore yuan business; Hong Kong, London, and Singapore.