You hold VOO, VTI, and QQQ. How many distinct stocks do you own? The answer is embarrassing.
- VOO and VTI overlap around 85% by weight; add QQQ and you are concentrating, not diversifying - Same mega-caps three times over is not a strategy - Every redundant fund adds complexity without diversification: messier rebalancing, murkier tax lots - Before adding a fund, check overlap; above 80%, you are duplicating - Overlap ignores borders; that international fund's top holdings are often the same multinationals
Overlap ($4.99 one-time) computes pairwise overlap for your whole portfolio, so the redundancy shows up before you buy it.