I keep seeing the same thing on Reddit. UK Muslims open a Trading 212 or InvestEngine account, search for halal, and end up buying 2 or 3 ETFs that hold almost the same companies. Here are the three most common overlap mistakes and how to fix them. MISTAKE 1: Holding ISWD and IGDA together. IGDA and ISWD are both developed market Islamic equity ETFs. They track similar indices with nearly identical geographic exposure — heavily weighted to the US, followed by Europe and Japan. Holding both means you are paying two expense ratios for essentially the same basket of companies. Fix: pick one. ISWD has slightly lower fees than IGDA. Or switch to HIWS which is cheaper than both at 0.17% TER. MISTAKE 2: Holding ISWD (or HIWS) plus MWIM. MWIM covers developed AND emerging markets. ISWD and HIWS cover developed markets only. If you hold ISWD plus MWIM, your developed market exposure is doubled while emerging markets barely move the needle in your portfolio. Fix: if you want global coverage including emerging markets, just hold MWIM alone. One fund, everything. If you only want developed markets, hold HIWS alone. MISTAKE 3: Holding HIWS and ISWD together. These two track different indices (MSCI Islamic vs Dow Jones Islamic Market) but the actual holdings overlap heavily. Both are developed market halal equity funds. The main difference is cost — HIWS charges 0.17% while ISWD charges 0.35%. Fix: hold HIWS if you want the cheapest option. Hold ISWD only if you specifically prefer the Dow Jones Islamic screening methodology over MSCI. THE SIMPLE RULE. One developed market ETF plus one emerging market ETF (like ISDE) if you want global coverage with separate control. Or one all-world ETF (MWIM) if you want everything in a single fund. Two funds maximum. That is all you need. Complexity does not equal diversification. Holding 4 halal ETFs that all track developed markets just gives you 4 expense ratios for the same exposure. What ETFs are you currently holding? Drop them below and I will tell you if there is overlap.