Could large numbers of black holes account for much of the “dark matter” estimated to exist in our universe?

This Hubble Space Telescope composite image shows a ghostly “ring” of dark matter in the galaxy cluster ZwCl0024+1652.

NASA, ESA, M.J. Jee and H. Ford (Johns Hopkins University)

No, because the universe never had the raw material to grow enough black holes to account for current estimates of dark matter.