...Cboe Global Markets has a leading position among options exchanges in the U.S. It has a 99% market share in index equity options and a 30.5% market share overall year to date through July (including single-name equity options). The company is more dependent than peers on volatile trading revenue. Transaction-related revenue represented about 63% of total revenue for Cboe in 2020--far above the levels for Nasdaq and ICE. Cboe operates with low leverage. S&P Global Ratings projects debt to EBITDA will be about 1.4x by the end of 2021. It is home to three of the most widely recognized products traded and used globally: VIX futures, VIX options, and S&P 500 options. VIX futures and options and S&P 500 options represented 52% of total net transaction fees in the first two quarters of 2021. Despite recent improvements, EuroCCP has weaker financial safeguards overall than most clearinghouses we rate. Netherlands-based EuroCCP, acquired in July 2020, is more concentrated than most other clearinghouses,...