Prestige is a measure of a player's Super Group's reputation.
The more Prestige earned, the more likely the Super Group is known and recognized by other. Prestige is used to buy a Super Group's Base, and outfit it accordingly.
Much like Influence, Prestige is earned by defeating enemies. Prestige can only be earned by a player while they are in Super Group mode, however.
This option can be activated by opening the Super Group window and clicking on "Enter SG Mode" All players in a Super Group (whether Security Level 1 or 50) can earn Prestige.
Prestige goes directly to the Super Group; it is not something a player keeps. If the player leaves the Super Group, the Prestige stays with the Super Group. Similarly, if a Super Group disbands, all the earned Prestige is lost.
At low levels, players in Super Group mode earn both Influence and Prestige unrestricted.
At higher levels, starting at level 25, characters in Super Group mode earn less and less Influence (and conversely more and more Prestige) until by level 34 they are only earning Prestige if in Super Group mode.