Private equity firms are carving out a more prominent position in the financial market as investment banking fees continue to rise, an article in Business Insider said.  

According to the article, fees  paid by private equity firms now make up 32% of U.S. investment banking fees. That's $6.5 billion out of $20.4 billion in total banking fees.

These firms have become investment banks' largest clients as they reap the benefits from the last buyout frenzy in 2007, now taking large companies public. Low interest rates from the Fed have also helped firms refinance previous deals.

The Blackstone Group was Wall Street's highest fee-payer last year at $880 million, the article stated. It is also one of the largest players in rental