Dimon Lobbies Whitehall Against Bank Tax Rise Ahead of October Budget

Jamie Dimon's direct call to a UK cabinet minister warning against higher bank taxation marks a significant escalation in the financial sector's pre-Budget lobbying campaign. JPMorgan is not a UK domestic lender, which makes the intervention notable — Dimon is arguing on behalf of London as a location for internationally mobile capital rather than defending a specific domestic P&L. That framing is deliberate and is the argument most likely to resonate with a Treasury balancing fiscal arithmetic against growth objectives. For markets, the October Budget now carries a discrete, dateable policy risk for UK banking equities, which have re-rated meaningfully on higher-for-longer net interest margins and are consequently the most visible target for a chancellor seeking revenue without touching headline income tax rates. The sector's valuation gap versus US and European peers already embeds a UK policy discount; a surcharge increase would widen it. Investors should watch for whether the government offers pre-Budget reassurance, historically the tell for how seriously Treasury is entertaining the measure. Absent that, UK bank shares are likely to trade with a persistent event premium into the autumn.