Here’s one place big banks are catching a break

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Wall Street's biggest banks have at least one thing to be thankful for in 2016.

The trend of smaller, private banks, also known as boutiques, gobbling up more and more revenue from mega-transactions finally may be reversing.

About one-third of the way into 2016, the percentage of cash earned on mergers and acquisitions by boutique banks is down to 17.6 percent, from an all-time high of 19 percent last year, according to Dealogic data. Boutique banks' share of deals was as little as 8 percent in 2008, and has shot up in the years following the global financial crisis.

So far in 2016, the boutique banks leading the way on M&A revenue are Centerview Partners, Evercore Partners and Moelis & Co., according to Dealogic. But those banks are leading in a year where there's a lot less to be made on fewer M&A transactions. None of the banks commented after being contacted by CNBC.com.