The invention relates to systems and methods for distributing encrypted market data updates to market participants via private multicast channels. Among other factors, characteristics of modern computer networks may cause participants to be sent (and to receive) their encrypted data for that update at different times. Thus, after the participants have all been sent their data for that update the system may then simultaneously transmit to those participants the key that will enable them to decipher their data via a public multicast channel such that all recipients receive the key at the same time. In this manner the invention may ensure that although participants receive their data in a given update at different times, they are unable to decipher that data until substantially the same time.