Globalization and liberalization have significantly heightened investors’ engagement in international markets, driving financial integration and intensifying stock market co-movements across the globe. Understanding these inter-market linkages is crucial for formulating robust macroeconomic policies and crafting strategic investment approaches that can effectively navigate an increasingly interconnected financial scenery. The current study provides a comprehensive correlation analysis among the calculated returns from India’s S&P BSE SENSEX and five prominent American stock indices—US (S&P 500), Canada (S&P/TSX Composite Index), Brazil (IBOVESPA), Mexico (IPC MEXICO), and Argentina (MERVAL)—over a 16-year period from June 3, 2003, to December 30, 2019. The analysis employs descriptive statistics to observe the nature of the calculated return series from the daily index closing data of six sample indices and carries on correlation measures to assess market integration among them. The normality test informed the application of the non-parametric Spearman Rank Correlation method. The findings reveal consistently weak correlations between the S&P BSE SENSEX and the American indices, highlighting limited financial integration and significant potential for portfolio diversification. In contrast, the study identifies strong association among the American indices, indicating high regional market integration and limiting diversification opportunities within the American markets.