Ackman's Pershing Square Holdings fund up 27 percent

Bill Ackman
David Grogan | CNBC
Bill Ackman

Billionaire investor William Ackman's Pershing Square Holdings fund has risen more than 27 percent this year after extending its gains modestly last month when many hedge fund managers suffered losses.

The Pershing Square Holdings fund inched up 0.6 percent in July. Ackman's performance has long been watched closely but never more so than now as the fund manager fights to try and seal a deal between drug companies Allergan and Valeant and periodically presents fresh evidence to underscore his argument that nutrition and diet company Herbalife is running a pyramid scheme, something the company denies.

Read MoreAllergan sues Ackman, Valeant, alleging insider trading

—By Reuters