A one-time high flying hedge fund is shutting its Hong Kong office

The stock-focused hedge fund firm, led by Dinakar Singh, has approximately 45 staff in total, spread between Hong Kong and New York, according to the person, who requested anonymity because the information is private. Of the staff, 15 are investment analysts or traders. No employees are based in Tokyo.

"The increasing volatility of the environment for fundamental investing means that the negatives of having too many people and too much exposure have increased dramatically, tipping the balance towards 'smaller and simpler,'" Singh wrote in the letter, which was sent Wednesday evening.

The firm will retrench to New York, though Singh wrote that he remains committed to global investing, including in Asia. The firm previously shut an office in London.

TPG-Axon managed approximately $1.6 billion in assets as of July 31, the person said. That is down from $2.4 billion in July 2015 and about $13 billion in early 2008. The firm was founded in 2004 by Singh, a former co-head of the principal strategies investment unit at Goldman Sachs.

Returns for TPG-Axon's hedge funds this year were unclear, but Singh noted "performance deterioration" in the portfolio in the letter, implying losses.

"Despite the turbulence of this year," he wrote, "I remain convinced that our fundamental analysis has led to a portfolio of stocks that are highly dislocated and with significant return potential."

Top U.S. stock holdings as of June 30, according to a public filing, included Allergan, Adeptus Health and GNC Holdings Inc. (Reporting by Lawrence Delevingne; Editing by Carmel Crimmins and Leslie Adler)