"There will be a shake-out among some of the ankle biters and some of the others," David Katz, a partner at Wachtell, Lipton, Rosen & Katz, said at the conference, referring to smaller activists.
However, the activism model is hardly in danger of extinction, bankers and lawyers said. Year to date, activists have launched 96 U.S. campaigns, a high historical figure, though 34 percent below the pace set in the same period in 2015.
Even top activists, however, acknowledge that the old play book of pushing for stock buybacks or quick sales is outdated. Starboard Value's Jeffrey Smith said recently that simply calling for a company to buy back shares "is not a plan," adding: "That does not create value."
The stock gains from such moves have already been squeezed. The S&P 500 buyback index, which measures the performance of the top 100 stocks with the highest buyback ratios, currently shows an 8.8 percent one-year loss.