This page explains how Tony Ma (USATT# 215463)'s rating went from 2121 to 2115 at the 2021 Butterfly/Sonesta Select Invitational Tournament held on 7 Oct 2021 - 10 Oct 2021. The links below take you to pages that describe various aspects of the rating processor.

The rating processor goes through 4 passes in order. The links take you to pages that provide detailed explanations of the calculations during each of the 4 passes.