Callaway Golf soared in Thursday trading after activist investor Jana Partners disclosed a 9.2% stake in the company.

Jana, founded by Barry Rosenstein in 2001, said it plans to discuss with Callaway selling all or part of the golf equipment and apparel maker despite what the activist acknowledged as successful innovation and durable market share in its core business.

The activist's position would make it the company's second-largest shareholder behind BlackRock, based on the most recent government filings.

Shares are "undervalued and represent an attractive investment opportunity," Jana said in a filing with the Securities and Exchange Commission.

Jana "intends to have discussions with the [Callaway's] board of directors and management regarding the Issuer's portfolio composition; strategic alternatives including exploring a sale of the Issuer or asset divestitures; capital allocation and acquisition strategy; operating performance and cost management; and governance," it added.

The stock rose 14.4% on Thursday to close at $18.19 a share.

Despite Thursday's sharp upswing, shares of Callaway have dogged the broader stock market in recent months, with much of the decline following the company's acquisition of outdoor apparel brand Jack Wolfskin earlier this year. Though CEO Chip Brewer lauded the $476 million purchase in January as an opportunity to provide "an innovative product offering with long-term synergies," investors have proven tougher to convince.

"It is not our practice to discuss individual shareholders. It is, however, the Board and Mgmt's practice to meet with shareholders to discuss the company's strategy in accordance with SEC regulations," a Callaway Golf spokesperson told CNBC.