The BCG matrix is a chart created by Bruce Henderson at Boston Consulting Group in 1970 to analyze business units and allocate resources. It categorizes products as Cash Cows, Dogs, Question Marks, or Stars based on their relative market share and the market growth rate. Cash Cows have high market share in a slow-growing market and generate cash. Dogs have low market share in a mature market and barely break even. Question Marks have low market share in a fast-growing market. Stars have high market share in a fast-growing market but require investment to maintain growth. The matrix is used to determine which products to invest in versus divest.