By Tom Hals

WILMINGTON, Del., June 9 (Reuters) - The only woman to serve on Delaware's Supreme Court, Carolyn Berger, announced her plans to retire from the key corporate venue on Sept. 1, according to an email from the justice.

Berger's announced departure comes after Governor Jack Markell said on Friday he was appointing Karen Valihura as his nominee to become the second woman on the five-member court.

Valihura, if confirmed by Delaware's Senate, will replace Jack Jacobs, who will be leaving later this month.

A majority of U.S. companies that have publicly traded stock incorporate in Delaware, which gives the companies access to the state's courts and its law that governs relations between management and shareholders.

The Delaware Supreme Court has ruled in the past year that Activision Blizzard Inc could proceed with its $8.2 billion deal with Vivendi SA and that Apollo Tyre Ltd did not have to close its $2.5 billion bid for Cooper Tire & Rubber Co.

Berger has been on the Supreme Court since 1994 and her term was to end in 2018. Prior to the Supreme Court she served on the Court of Chancery from 1984 to 1994.

Former Chief Justice Myron Steele retired last year, which set in motion a series of major changes in Delaware's courts.

Leo Strine, chief judge of the nationally prominent Court of Chancery, the first stop for corporate disputes, was elevated to replace Steele. Andre Bouchard left his private practice in Delaware to replace Strine.

The two remaining Supreme Court justices from the Steele era, Randy Holland and Henry duPont Ridgely, have both been on Delaware courts long enough to qualify for full retirement benefits. As a result, there has been speculation in the Delaware legal community that they may decide to retire before their terms end in 2023, for Holland, and 2016 for Ridgely.

(Reporting by Tom Hals; Editing by Lisa Shumaker)