This thesis studies the impact of contractual mechanisms in MeA valuation deals and proposes three models to evaluate them. Also, under the Contract Theory lens, we draw attention to the parties behavior and its impact on clauses settings or transaction success. First, we develop a model for earnouts and provide the foundation for understanding how they might best be structured and how their value might be estimated, especially considering their similarity to financial options. Furthermore, we also test different features for the earnout, such as binary options and a combination of binary and call options. Second, we model the anti-dilution covenant, which provides additional protection for investors, especially in a venture capital context. Antidilution plays an important role as insurance for venture capitalists against down round, which is a subsequent financing event at a lower valuation. Lastly, we developed a valuation model for liquidation preference, which can be an alternative guarantee for investors in MeA deals. Liquidation preference is typically defined as the right of the investor (usually holding preference shares), to receive its investment amount plus a certain agreed percentage of the proceeds in the event of a liquidation of the company, in preference over the other shareholders. Our findings indicate that the typical legal covenants used in MeA deals have a relevant impact on their fair value and may work as important tools to bridge the gap between the buyer and the seller, especially considering the information asymmetry on this context. On the other hand, depending on the clauses settings, the risk may be too skewed to the seller side, making the deal structure too expensive under his perspective. By testing the model s parameters sensitivity, we provided the inputs the seller needs to evaluate and pursue the optimal contractual terms.