Used in the context of general equities. Number between 0 and 1 that measures the strength of correlation of movement between the portfolio/ stock and the index . Indeed, the R2 is the square of the correlation. For hedging purposes, the higher the R2 the better.
PORTFOLIO R2
Meaning of PORTFOLIO R2 in English
Campbell R. Harvey. Hypertextual finance English glossary. Английский словарь гипертекстовых финансов. 2012