According to Delta, "Shared Rewards" are the payments for meeting monthly corporate operational targets, and are distinct from annual profit sharing. For example:
http://news.delta.com/2014-02-14-Delta-Employees-Earn-506-Million-in-Profit-Sharing-for-2013-Performance
Along with base pay, Delta provides employees with additional compensation elements like profit sharing, designed to allow employees to earn more when the company performs well. Additionally, Delta employees can earn monthly bonuses for meeting corporate operational goals throughout the year, known as Shared Rewards.
In 2013, Delta employees help achieve the corporate financial and operational goals earning $91.7 million in Shared Rewards, which, combined with profit sharing, totals $598 million in bonus performance pay for the year. Delta has paid out nearly $1.7 billion in profit sharing and Shared Rewards during the past four years.
http://news.delta.com/2014-02-14-Delta-Employees-Earn-506-Million-in-Profit-Sharing-for-2013-Performance