With bigger fish to fry, Relational exits Ceridian....

Activist investor Ralph Whitworth of Relational Investors who's been pushing for changes at Ceridian has sold his stake in the company:

Relational founder Ralph Whitworth, explaining his exit, said he had "bigger fish to fry." He declined to elaborate in a brief phone interview.

Ceridian has been battling with William Ackman's Pershing Square Capital Management, a hedge fund and a 14.3 percent shareholder which wants the company to spin off its Comdata division and replace its board.

The two activist investors have been up in arms since Ceridian decided instead to put the whole company up for sale.

Activist fund Relational sells all Ceridian shares - Reuters