With emerging-market bonds heading for a fourth-straight year of over-sized gains and burgeoning assets, funds focusing on more exotic corners of the world could be facing increased headwinds in 2013.

Through November, investors had poured more than $25.4bn into the category using mutual funds and exchange-traded funds, according to Morningstar. That was more than all of last year's net inflows and helped push assets by the group past $88bn - some 65% more than 2012's record-setting total.