The Indonesian beverage industry is highly competitive as listed companies pursue growth amid shifting consumer preferences. PT Akasha Wira International Tbk (ADES) was selected because its 2021 product diversification provides a distinct strategic event for analysis, while its long history as a listed company and availability of quarterly financial disclosures enable a sufficiently long time-series examination of financial fundamentals and stock performance. This study examines ADES’s stock performance relative to its financial fundamentals, evaluates differences in performance around the 2021 diversification, and benchmarks its financial position against PT Sariguna Primatirta Tbk (CLEO). Using quarterly data from 2012 to mid-2026, the study applies OLS regression to test the association between stock return and four fundamental ratios—liquidity, leverage, activity, and profitability—along with a two-sample F-test and Welch t-test comparing pre- and post-diversification returns, and a comparative DuPont analysis against CLEO. The findings show that profitability is the factor most consistently associated with ADES’s stock return, that the post-diversification period shows both higher returns and volatility, and that ADES’s profitability advantage over CLEO is primarily margin-driven rather than leverage-driven. The study contributes to financial management theory by showing that the relevance of fundamental ratios can vary by firm and period, and offers investors and managers a practical reference point for evaluating firms undergoing product diversification in Indonesia’s consumer-goods sector.