Blackstone Property Partners is expected to close the deal by early 2019.: Blackstone is buying 800th Fifth Avenue in Seattle for $540m (€475m) on behalf of its US core-plus real estate fund. The 934,000sqft office property is being sold by JP Morgan Asset Management and Hines, according to sources familier with the transaction. The acquisition by the $29.8bn open-ended Blackstone Property Partners fund is expected to be completed by early 2019. JP Morgan is the majority owner and Hines is the operating partner. The two parties completed a $46m renovation last year.