Herbalife Ltd. (NYSE: HLF) shares gained 0.7% to $39.02, ahead of its fourth-quarter earnings. The nutritional-supplement company has been at the centre of a public dispute between activist investor Carl Icahn, who disclosed late Thursday a 12.98% stake in the company, and hedge-fund manager William Ackman, who has accused the company of being a pyramid scheme and said he shorted its stock. Share volume totaled 270,000 compared to an all-day average of 1.2 million