Westwood-based investment firm Shamrock Capital Advisors has sold its majority stake in San Francisco-based advertising company Giant Creative Strategy.

The transaction is valued at up to $97 million.

Shamrock Capital Advisors claims $1.9 billion assets under management in media, entertainment, and communications.

On July 18, Shamrock Capital announced that it had completed the sale of its healthcare marketing agency to Huntsworth, a London-based healthcare and communications company.