The Circuit Court of Cook County granted class certification to Chicago Mercantile Exchange members with Class B memberships who allege the switch to electronic trading changed their trading rights and privileges and devalued their shares by more than $1 billion.CME Group, Inc. is the world’s largest futures and options exchange company, with annual revenues of more than $3.6 billion.It operates through various futures exchanges and trading platforms, including CBOT, otherwise known as the Board of Trade of the City …