(Bloomberg) -- The energy fund at Zimmer Partners posted its worst quarter ever after sinking about 46% in March as oil markets plunged.

The fund dropped 55% in the first quarter after losing money each month, according to an investor letter seen by Bloomberg. The fund, which ran $1 billion at the end of January, now has about $500 million in assets.

The oil price war between Russia and Saudi Arabia ravaged the energy industry last month and helped send Brent crude to its lowest in nearly two decades. Making matters worse, the coronavirus pandemic has wiped out demand for crude amid an oversupply threatening the survival of oil producers and the economies of oil-dependent nations.

Zimmer’s energy fund, which started in October 2014, didn’t stand much of a chance in these markets. It is long-biased, meaning it mostly wagers that stocks will rise. The fund focuses on areas including electric and gas utilities, renewable and independent power producers, midstream infrastructure companies and explorers and producers. Its worst calendar year was 2015, when it lost almost 9%.

The fund is benchmarked to the Alerian MLP Infrastructure Total Return Index, which fell 48% in March and 58% in the quarter.

A spokesman for the New York-based firm, which oversees about $3.4 billion, declined to comment.

Zimmer’s larger pool, the $2.7 billion Utility Fund -- which is designed to be uncorrelated to the energy, utility or infrastructure sectors as well as the broader market -- has fared better. It lost 4.7% last month and 4% for the quarter, another document shows. The fund, which invests in utilities including electric, gas and telecommunications companies, started trading in 1997 and has never had a down year.

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