Months after announcing it would radically revise its investment strategy by the end of the fiscal year, Harvard Management Company will invest at least $300 million into a hedge fund formed by some of its former money managers. The money is earmarked for a hedge fund formed by former HMC employees Michele Toscani and Graig Fantuzzi, two investors who previously served as portfolio managers at the University’s struggling investment arm. The two departed earlier this year after HMC’s Chief Executive Officer N.P. Narvekar announced the firm would cleave its internal staff in half.