Come earnings season, many male research associates (and some analysts) begin to rock what has become known as the "earnings beard."*
It starts simply enough. Once smooth faces will go unshaven for an extra day. Then another day, and another, until perma-stubble sets in.
At that point the associate realizes:
1) they're too tired to care
2) no one else really cares since they're not meeting with clients
3) they don't really trust themselves with a razor at this point
Thus the earnings beard is born.
*Of course, this depends on the firm's dress code, but thats a topic for another day. The earnings beard usually goes hand in hand with taking casual fridays to their logical, yet ridiculous extremes.