D1 Capital Partners, a hedge fund managed by Dan Sundheim, experienced a 6% decline in its equities book during March, making it one of the worst-performing stock-pickers for that month. The downturn was driven by losses in its six largest stock investments, particularly in Flowserve Corp., which fell 17%, and James Hardie Industries, which dropped 22%. Despite this setback, D1 is still up 2.7% for the year. The firm successfully raised $2.7 billion for a new fund focused on private investments, along with an additional $300 million for co-investments, allowing clients to participate in specific deals. The broader market faced challenges in March as stocks and bonds fell, while oil prices surged amid escalating tensions in the Middle East due to US and Israeli actions against Iran. Other hedge funds, such as Viking Global Investors and Tiger Global Management, also reported declines, with Tiger falling 7.3%. D1 Capital, which manages $35 billion, has increasingly focused on venture capital and late-stage growth investments, with significant returns from its bet on SpaceX, which accounted for 45% of its private exposure last year.