Alternative asset managers Hillhouse Investment Management, Ltd., Boyu Capital Group Management Ltd. and CDH Investment Management Company Limited are in advanced talks to invest in GDS Holdings Limited (NasdaqGM:GDS)?s data center business outside China, according to people familiar with the matter. An agreement on a total investment of $500 million to $600 million may be reached as soon as the coming weeks, though no final decisions have been made, the people said, asking not to be identified because the matter is private. Other investors could also be involved in a deal, they said.