Shares of Herbalife Nutrition Ltd. tumbled 7.3% in morning trade Friday, after its largest shareholder, Icahn Enterprises LP disclosed that it was looking to trim its stake. Icahn Enterprises (IEP) said it was tendering up to 11.4 million Herbalife shares, or about a quarter of the 45.7 million shares, or 25.9% of the outstanding shares, it currently owns. Icahn Enterprises first acquired Herbalife shares at the end of 2012. Since then, of the 29 positions IEP holds, only three have been held longer than Herbalife. "For almost six years, we have been one of Herbalife's strongest, most loyal supporters; we stood by the company through a half-decade long short-selling campaign; and we never sold a share, even after our investment doubled, said IEP Chairman Carl Icahn in a statement. "But, given that our Herbalife investment has become an outsized position, representing approximately 24% exposure to total [net asset value], it is only prudent for IEP to reduce its exposure." In February, Bill Ackman's hedge fund Pershing Square Capital reportedly exited its $1 billion short bet on Herbalife. Herbalife shares have soared 59% year to date through Thursday, while the S&P 500 has gained 2%.