As China yanks down its currency to kick out short-term speculators, one set of investors isn't budging: global money managers snapping up offshore yuan bonds.

Since the middle of February, issuers including Caterpillar Inc., BP and an arm of the World Bank have sold a combined $2.4 billion of yuan-denominated bonds outside mainland China, receiving strong demand. Since the beginning of this year, 29 new yuan bonds have been issued totalling $6.5 billion, almost triple the same period last year, according to data provider Dealogic.