In one sense, all 34 banks that underwent the Federal Reserve's annual stress tests were winners: They received approval for their dividend and stock-buyback plans.

In aggregate, the group is expected to increase capital distributions to nearly 100% of its net earnings over the next four quarters, a major hike from 65% last year. Still, some of the banks fared better on reviews of their financial strength than others, and the size of approved payouts relative to earnings was varied.

The assessment of 34 large financial institutions, known as the Comprehensive Capital Analysis and Review, is vital for banks seeking to reward investor loyalty. It was set up in the aftermath of the 2008 financial crisis, when a number of financial institutions increased payouts despite rising defaults in the $15 trillion U.S. mortgage market and dour assessments from analysts.

Following is a closer look at the biggest winners, and the comparative losers, in this year's review.