Though it may feel like high-frequency trading is taking over the world, volume actually has been pretty flat in 2014, according to the latest industry data.
Trading activity averaged 903 million shares a day in March, about the same as February and slightly below January's 912 million, according to data from Tabb Group, which compiles a monthly list of information from 42 of the largest off-exchange trading platforms.
On a yearly basis, alternative trading system, or ATS, volume increased about 12 percent, but the total that came from dark pools—which don't report their activity either to the Nasdaq or New York Stock Exchange—was about flat as well. The flattish trading activity seems to match a trend in which fewer firms are entering the crowded offline/dark pool/high-frequency trading space.
"The number of registered ATSs has kind of plateaued," Sayena Mostowfi, Tabb's senior equities analyst, said in an interview. "We predict in the upcoming year we're actually going to see a decrease."