After only two years in the ETF business, Maryland-based ProShares passed the $20 billion mark in assets under management.

The firm specializes in leveraged and short exchange traded funds and has introduced 64 ETFs in just two years.

Leveraged and short ETFs are used in investment strategies and to hedge portfolios.  The ETFs are linked to broad indices such as the S&P 500 (SSOSHSDS) and the Nasdaq-100 (PSQQIDQLD) as well as to sector and foreign equity indices.

ProShares recently launched the first ETF that provides short exposure to Treasury securities.