Market Share in retail is the portion or percentage of total sales within a specific market that a company or brand holds. It is a key performance indicator that reflects a company's position relative to its competitors in terms of revenue and customer base. Calculated by dividing a company's sales by the total market sales and multiplying by 100, market share provides insights into a business's relative strength and competitiveness. High market share often indicates a strong presence, while changes in market share can signify shifts in consumer preferences or competitive dynamics, influencing strategic decisions in the retail sector.