Brevan Howard Asset Management’s flagship hedge fund lost 2.85 percent in March, erasing all of its gains from the start of the year, according to an investor letter seen by Bloomberg News. The decline means the Brevan Howard Master Fund, which managed $10.8 billion as of February, ended the first quarter down about 2.4 percent. By comparison, the HFRX Macro/CTA Index has lost almost 1 percent in 2017. A spokesman for the investment firm run by billionaire Alan Howard declined to comment. Macro hedge funds faced an investor backlash last year as clients pulled almost $10 billion following years of middling performance caused by central...