Alpaca uses IEX and SIP feeds to provide market data to its users.

The Free plan consists of data from IEX (Investors Exchange LLC).

For the Unlimited plan, we receive direct feeds from the CTA (administered by NYSE) and UTP (administered by Nasdaq) SIPs. These 2 feeds combined offer 100% market volume.

Details on what feeds are available, additional differences between Free and Premium data subscriptions, and more are available here.