The vacancy rate on homes that collateralize single-family rental securitizations rose ever so slightly to 4.3 percent in May, but high renewal rates on tenant leases were strong, according to figures compiled by Morningstar Research. The firm noted that the average retention rate rose for the fourth straight month and now stands at 79.8 percent “for the most recent data available.” Two SFR securitizations, including one from market leader Invitation Homes, paid off...