Delivering Alpha: In 'golden age' for activists, 12 firms to watch

Carl Icahn on Ackman, activism and delivering alpha

Underperforming corporate executives beware: The activists are coming for you.

It's been a banner, possibly record-breaking, year for the activists who swarm boards and demand change, sometimes in high-profile media campaigns, other times in more low-key approaches to wrest control of companies and forcefully implement their agendas.

In all, there have been 64 such cases this year, 3½ times as much as 10 years ago and well on pace to eclipse 2014's standard of 102, according to S&P Capital IQ.

"We have reached a golden age of investor activism," S&P Capital IQ said in a report. "The success of investor activism has helped these firms both attract more capital and deliver greater returns as their principals now regularly make news and headline events. Many of them have become household names who literally move markets."

Read More Big winners, bigger losers from 'Delivering Alpha'

The biggest names in investor activism will be on hand Wednesday at "Delivering Alpha," the annual investor conference presented by CNBC and Institutional Investor. They include Carl Icahn and Bill Ackman, two rivals who literally hugged out their differences at last year's event. Others to be on hand include Nelson Peltz of Trian Fund Management and Paul Singer of Elliott Management. Yet another panel will feature Keith Meister of Corvex Management, Tom Sandell at Sandell Asset Management and Jeffrey Smith of Starboard Value.

Multiple factors have helped drive the success of activists. They include a bull market in equities, low revenue growth, swelling cash balances on company balance sheets, and, of course, strong results, which breed more activist efforts.

"Investor activism has become a leading influence in our capital markets today unlike in the past when these so-called corporate raiders were viewed as an anomaly for public company dealings," the S&P Capital IQ report said. "Now they are shaping boardroom discussions regardless if a company has been targeted directly or indirectly with activity in its peer group."

Some of the highest-profile cases include Icahn's maneuvering at Apple and Family Dollar and Ackman's continuing war against Herbalife and his efforts at JCPenney. David Tepper's Appaloosa Management this year took aim at General Motors, while Dan Loeb's Third Point has been in a high-profile struggle with Sotheby's.

But where are the next big battles going to happen?