The low volume trades is reflected by large benchmarks’ low day-to-day volatility. For instance, the Dow Jones Industrial Average has only made one 2% or more daily move this year, whereas the Dow has spiked 2% or more 10 times by this time of year in 2010 and 33 times in 2009 for the same period.

“If it’s this slow now, I’m dreading July and August,” Antonelli added.

The dip in trading activity is weighing on financial firms. For instance, U.S. banks like J.P. Morgan Chase (NYSE: JPM), Bank of America (NYSE: BAC), Citigroup (NYSE: C), Goldman Sachs (NYSE: GS) and Morgan Stanley (NYSE: MS) have seen total employment fall 9% since the end of 2011 as revenue remains flat.

The iShares U.S. Broker-Dealers ETF tracks U.S. investment banks, discount brekerages and stock exchanges. Looking at its underlying holdings, GS is 6.6% of IAI’s portfolio and MS is 6.5%,

iShares US Broker-Dealers ETF

For more information on brokerage firms, visit our broker dealers category.

Max Chen contributed to this article.