Why is the volume on BATS (CBOE) lower than other exchanges?

QUODD offers the BATS RealTime API that provides real-time stock quotes and market data for US equities traded on the BATS Exchange, now known as Cboe U.S. Equities. In addition to price, volume and stock quotes (bid/ask) information, this API provides tick-level market data, and other market statistics including open, high, low, close, volume data for stocks, depository receipts and ETF trading on BATS (Cboe U.S. Equities).

BATS trading represents approximately 6 - 7% of US market activity. The BATS volume reflects the volume of trades performed only on BATS, and does not reflect trades executed on other venues, such as Nasdaq or NYSE. As a result, the BATS trading volume will not match the composite volume of all trades that occurred on all exchanges. If you suspect our BATS data might be incorrect, please verify prices against the BATS website.