The article examines market efficiency for stocks using different metrics. A model was created to show how factors like transaction costs, short sales costs, and investor valuations affect market efficiency. The study found that transaction costs have the biggest impact on market efficiency, followed by short sales costs and investor valuations. The Fama-French Factors were also found to play a role in these relationships. Market efficiency was shown to be linked to various market activities, with differences between Nasdaq and non-Nasdaq stocks.