Hyatt launched their earning and redemption partnership with Small Luxury Hotels of the World at the end of 2018. Initially they only brought about 10% of SLH’s 500+ properties into their portfolio.
They followed two months later with another 56 properties or 10% and then 57 more a month after that. Now they’ve added another tranche of hotels where you can earn and redeem Hyatt points, bringing them to over 200 (or roughly 40% of) SLH properties in the portfolio.