Block jumps after S&P Dow Jones says stock to join S&P 500

** Block XYZ jumps 8.9% to $79.35% premarket

** S&P 500 Dow Jones Indices says financial tech firm to replace Hess HES on S&P 500 SPX effective before market open on Wednesday, July 23

** S&P Dow Jones noted Hess has been acquired by Chevron CVX

** ASX-listed shares of Block XYZ jumped as much as 11.7% to A$122.59, highest since February 21

** YTD, XYZ falls 14.3%