Abstract- Portfolio managers hoping to diversify across Indian financial sectors might want to rethink their strategy. The data points to a harsh reality: these markets move in lockstep.We ran the numbers on daily closing prices from January 2014 through December 2024. The focus? The benchmark Nifty 50 alongside major sectoral indices—specifically Nifty Bank, Financial Services, Private Bank, and PSU Bank. Sure, the indices are non-stationary on the surface. But run a Johansen Cointegration test, and a clear long-term equilibrium emerges. They are tightly linked.Short-term imbalances do happen, though. Market inefficiencies actually linger longer than you might expect. Our Vector Error Correction Model (VECM) flagged a surprisingly sluggish adjustment speed of just -0.023 back toward equilibrium.So, who leads the dance? The broader market. Pairwise Granger Causality tests show the Nifty 50 pulling the strings, directly driving the performance of the Nifty Private Bank index rather than the other way around.The takeaway here is pretty straightforward. Spreading capital across these highly integrated financial sectors won't offer much long-term protection or genuine diversification.