Assets in U.S.-listed exchange-traded funds and exchange-traded notes rose 39% from a year ago to $1.098 trillion at the end of June, up from nearly $788 billion at the end of June 2010, the National Stock Exchange said.

In addition, the number of ETFs and ETNs rose 28% to 1,288, up from 1,009.

Inflows to ETFs and ETNs through the first six months of the year totaled $58.6 billion, a 47% increase from inflows of $39.9 billion in the first six months of 2010.