Malaysian stocks were down 0.2% and the ringgit 0.1% weaker despite government data showing exports jumped 31% in March from a year earlier, rising at their fastest pace in nearly four years.
Asian currencies and bonds have lagged as the prospect of more government spending under a Joe Biden administration pushed up US treasury yields earlier this month, reducing the appeal of some of the region's high-yielding government debt.
"The rupiah may continue its outperformance the global hunt for yields should drive more inflows into its bond markets which would be a major supportive element for the Indonesian currency," Tan added.
Investors poured money into Asian equities last month, helping both stock and currency markets recover further from losses in the first quarter's coronavirus-driven sell-off.