Hedge fund firms and other alternative asset managers are playing an increasingly important role in financing the economy, according to a new paper published by the Alternative Investment Management Association (AIMA), the global hedge fund association.

The paper says that private debt funds such as hedge funds now manage around $440 billion in assets, with some $64 billion of new capital allocated to the sector in 2014 alone.

The paper finds that the most popular borrowers of non-bank private debt are small and medium-sized enterprises (SMEs). Such businesses are typically too small to raise capital through the public corporate bond market and have been finding it difficult to borrow from the traditional banking sector since the crisis. Refinancing existing loans, pursuing acquisition and expansion plans and improving working capital are all common uses of such private finance.