NEW YORK (Reuters) - Six closely watched investors sliced their stakes in Allergan Plc (>> Allergan, Inc.) during the first quarter, recent regulatory disclosures show, cutting what had been one of the years' best performing health stocks that has stumbled in recent days.

Billionaire investor Carl Icahn sold out of the pharmaceutical giant entirely, while Farallon Capital Management LLC, David Tepper's Appaloosa LP and Seth Klarman's Baupost Group LLC were among those trimming their stakes by as much as 32 percent, according to regulatory filings.

Paulson & Co Inc and Leon Cooperman's Omega Advisors Inc also pulled back on the stock during the quarter, their filings showed.

The Botox-maker recorded a strong rally in early February after seeing strong sales, but it posted a first-quarter loss last week as it took a nearly $2 billion write-down on the value of its stake in Teva Pharmaceutical Industries (>> Teva Pharmaceutical Industries Limited).

William Blair & Co LLC analysts Tim Lugo and Raju Prasad said in a note last week that the company's eye care business also faced some potential challenges this year.

President Donald Trump and his Republican party are pushing for a tax reform that could include a border-adjustment measure to satisfy Trump's interest in promoting U.S. manufacturing by taxing imports and exempting export revenues from taxation.

Allergan Chief Executive Brent Saunders has said he does not anticipate U.S. tax reforms this year but that an import tax could hurt the Dublin-based drugmaker.

Omega and Paulson offered no comment, while the other four investors did not respond to inquiries from Reuters. Allergan declined to comment.

Shares in Allergan were up 13.77 percent in the first quarter.

The quarterly disclosures of manager stock holdings with the U.S. Securities and Exchange Commission, in what are known as 13F filings, are always intriguing for investors trying to divine a pattern in what savvy traders are selling and buying.

But relying on the filings to develop an investment strategy comes with some peril in part because the disclosures are backward looking and come out 45 days after the end of each quarter.

Still, the filings offer a glimpse into what stocks fund managers saw as opportunities for profit.

(Reporting by Trevor Hunnicutt; Additional reporting by Lewis Krauskopf and Carl O'Donnell; Editing by Jennifer Ablan and Andrew Hay)

By Trevor Hunnicutt