Correlation(P,M) = 1 for well-diversified Portfolios - more details required

[karlsaccr]

Hi all,

There is a concept that I am not able to grasp properly, in Topic1.Ch5.VidLecture#2 it was stated that: in a well diversified portfolio the Correlation between Portfolio and the Market is +1 which means that the movement of the Market and the Portfolio are synonymous


Can somebody elaborate more on that ?

Thank you