**Share of Market (SOM)**, **SOV (Share of Voice)**, and **Excess Share of Voice (ESOV)** are three key high-level metrics related to the field of [[Marketing & Analytics]]. ^about For any given [[Business]]: > **Share of Market (SOM)** indicates what percentage of 'the market' is considered their customer base > **Share of Voice (SOV)** indicates what percentage of 'advertising space' is dominated by them > **Excess Share of Voice (ESOV)** is SOV less SOM, i.e. how much more advertising space is the business dominating than its current market share would indicate. ESOV can be (and was originally developed as) an indicator for the expected growth (or decline) of a business's SOM. Theoretically, the 'amount' of advertising is a key driver in creating new customers, winning over competitors' customers, and retaining your existing customers. Performance 'on par' with your current market share (ESOV of zero) will retain it, outperforming competitors (positive ESOV) will gradually increase it, while falling behind (negative ESOV) will lose it. Note that 'the market' and 'advertising space' and 'amount' and 'on par' are simplistic and subjective in this context, and need to be consistent within any given analysis for these metrics to bear significance.