Harvard University’s N.P. “Narv” Narvekar is doubling down on an investment that has fallen out of fashion: hedge funds. Narvekar’s bet on the sophisticated, high-cost brand of money manager marks the biggest since the university hired him in 2016 to turn around the lagging performance of its $39 billion endowment. Over the two years ended in June, the largest fund in higher education almost doubled its investment in hedge funds, which now total $13 billion, university filings show. Harvard’s hedge funds comprise a third of the endowment, compared with roughly a quarter at Yale and Princeton.