In finance and investing the correlation coefficient is used to calculate a statistical measurement of how strong movements in two markets are historically in relation to one each other. The correlation is expressed in a range of values between 1.0 and -1.0. All the readings of the formula are inside the 1.0 to -1.0 range. So any calculations that come out to more th“Diversification is the only free lunch” in investing, says the quote attributed to Nobel Prize laureate Harry Markowitz.an 1.0 or less than -1.0 are an error. A -1.0 shows a perfect inverse correlation in movement. One market goes up by the same ... (full story)