Keyur Khamar/PGA TOUR

Callaway Golf Co.  (ELY - Get Report) shares surged Thursday after activist investor group Jana Partners revealed a significant stake in the struggling sports equipment maker just hours ahead of the opening round of the U.S. Open.

Jana said it hopes to use its 9.22% stake, which was acquired as of June 3, to "exert negative control over the important corporate actions" of Callaway and propose new members to its board. Jana also said it may also wish to build a bigger stake, or completely acquire, the Carlsbad, California-based group. It may also move to sell it completely.

Callaway shares were marked 14.3% higher in the opening minutes of trading on Wall Street Thursday, changing hands at $18.16 each. Prior to today's move, the shares have been virtually unchanged for most of the year. 
 
TheStreet's founder, Jim Cramer, recommend Callaway Golf shares to his Mad Money audience on CNBC earlier this week, saying the recent pullback has make the group an attractive option in the sports equipment space.
 
Last month, Callaway lowered the revenue growth guidance for its acquisition of Jack Wolfskin, a maker of outdoor apparel, to between 4% and 6%, a figure that would trail prior estimates of a $382 million tally. For the full year, Callaway expects to earn between 96 cents and $1.06 per share, with revenue between $1.67 billion to $1.7 billion.