Cross-border yuan settlements by the Bank of China Ltd increased more than 50 percent year-on-year during the first nine months of 2013, faster than the nation's 7.7 percent trade growth, according to the bank's Cross-border RMB Index released on Thursday.

The bank developed the CRI to reflect the use of the currency in cross-border and overseas transactions. The index has three inputs: yuan outflows, transactions overseas and yuan inflows.

The bank's cross-border yuan settlements reached 2.67 trillion yuan ($438 billion) from January to September, up 56 percent year-on-year and more than the full-year value for 2012.

"Cross-border yuan settlement has become an increasingly important part of the bank's international business portfolio," Vice-President Chen Siqing said during a news conference. "We continue to take the lead in cross-border yuan settlement among domestic banks."

BOC's cross-border yuan settlements account for about one-third of the market. The bank has settled 7.2 trillion yuan in cross-border transactions since the pilot program was launched in 2009, the largest settlement value among domestic participants.

The China (Shanghai) Pilot Free Trade Zone is expected to become another important yuan offshore market, said Chen. BOC has formulated plans to promote cross-border yuan settlement in the FTZ, although those plans haven't yet been announced, he added.