Wall Street investors are hoarding $971 billion - here's who stands to benefit when they start spending

Private equity firms are sitting on billions of dollars of cash.

They have $971 billion in untapped capital, also known as dry powder, according to research firm Preqin. That has led many to ask when private equity firms will start spending that cash.

Investment banks view private equity- or financial sponsors- as one of their best clients because of the hefty fees they receive for repeatedly working on deals and getting them done.

About 16% of the total fee pool in the first half of 2016 stems from financial sponsor-related fees, according to data provided by Dealogic.

Goldman Sachs won the most business from financial sponsors in the first half of 2016, according to Dealogic followed by JPMorgan and Barclays. Here's the top five: