Richard Demille Wyckoff (November 2, 1873 – March 7, 1934) was an American stock market investor, and the founder and onetime editor of the Magazine of Wall Street (founding it in 1907).

He grew his wealth such that he eventually owned nine and a half acres and a mansion next door to the Hamptons estate of General Motors president Alfred Sloan in Great Neck, New York.

He turned his attention and passion to education, teaching, and in publishing exposés such as “Bucket Shops and How to Avoid Them”, which were run in New York's The Saturday Evening Post starting in 1922.

Wyckoff worked with and studied them all, himself, Jesse Livermore, E. H. Harriman, James R. Keene, Otto Kahn, J.P. Morgan, and many other American investors of the day.

The Wyckoff technique may provide some insight as to how and why professional interests buy and sell securities, while evolving and scaling their market campaigns with concepts such as the "Composite Operator".