This study aims to analyze the firm-specific errors (FSSE) as a proxy for mis-valuation and the long-run value-to-book ratio as a proxy for growth opportunities during mergers and acquisitions. In this study, the researcher used the RKRV methodology, which was developed in 2004, to analyze firm-specific errors and future growth opportunities by decomposing the market-to-book ratio in the merged organization of the Pakistani financial sector. The researcher used the mergers and acquisitions data from the financial sector from 2000 to 2021. For the purpose of analysis, the researcher prepared one year of pre-merger and three years of the merger performance of merged financial institutions and compared it with nonmerger financial institutions. The results of non-zero log differences between market values and fundamental values show that in Pakistan firms, firm-specific errors (FSSE) exist in the merged and nonmerger financial institutions. The second component of this methodology was to calculate the long-run value of the book (LRVTB) by taking the difference between the estimated market value and the firm's book value as a proxy for long-run growth opportunities. The results show that no long-run growth opportunities exist in Pakistan's merged and non-merged financial institutions because the difference between estimated market value and book value is negative. The third component of this study is to estimate time series sector error (TSSE) by taking log differences between fundamental value and estimated market value if the firm-specific error exists in the valuation of firms and there are no long-run growth opportunities. The results show that time series sector error also exists in the valuation of financial institutions. The researcher concludes that the mergers and acquisitions intentions are to meet the minimum capital requirement enforced by The State Bank of Pakistan. The merger and acquisition activities that took place during the years 2000 to 2011 are the legislative mergers. The results satisfy the economic shocks theory. There is no issue of agency problems, whether mergers are successful.