Interest rate cuts are coming, and the Big Four banks could be in for a challenging time. But while HSBC, Barclays, Lloyds, and NatWest navigate the treacherous waters of falling margins, a quieter revolution is unfolding in the FTSE 250.
Here, nimble challenger banks such as OSB Group (LSE: OSB) and Metro Bank (LSE: MTRO) are plotting a different path forward. While they represent two very different investment theses, both offer compelling reasons to consider them as part of a diversified, income-focused portfolio in 2026.
Why challenger banks?
Here’s the uncomfortable truth for the Big Four: when interest rates fall, their profit factories slow. These heavyweight lenders depend on wide margins — the spread between what they pay savers and what they charge borrowers. Lower rates squeeze those margins, which is why FTSE 100 banks are justifiably nervous about the Bank of England’s expected rate cuts in 2026.
Challenger banks however, operate a different playbook. In most cases, they’ve built lean, technology-driven operations with lower cost bases and strategic niche focus. They don’t compete on the same terms as the Big Four. More importantly, they’ve already navigated the turbulent waters of earlier near-collapses or restructuring, pricing in risk and making it more manageable.
For example, Metro Bank’s 2023 crisis was brutal, with 1,500 job cuts, branch closures, and underperforming loan book sales. It was a painful restructuring but resulted in a lean, focused, and strategically-positioned bank operating high-margin lending segments like corporate, commercial, and SME banking.
Meanwhile, OSB’s maintained steady profitability with a razor-sharp 40% cost-to-income ratio, demonstrating operational discipline even as margins compress.
Two opportunties, two angles
OSB Group’s the immediate income solution here, with a 5.4% dividend yield — far higher than the FTSE 100’s average. The bank raised full-year profit guidance to at least £300m for 2026, signaling management confidence amid economic uncertainty. Wth a price-to-earnings (P/E) ratio of just 4.9, it’s trading at a significant discount to the market, suggesting growth potential if execution continues.
Still, it’s not immune to economic policy changes. In H1 2025, the bank’s earnings declined 20% year-on-year due to lower net interest income. It must meet its guidance targets or risk shaking investor confidence.
Metro Bank’s the more speculative play, but arguably the more exciting one. The bank returned to profitability in 2024 and is targeting double-digit returns in 2026, and mid-to-upper-teens thereafter. Its net interest margin’s expected to expand from 3% to nearly 4% this year, driven by disciplined asset rotation toward higher-yielding corporate and SME lending. If the bank executes this move successfully, it could be the turnaround story of 2026.
But its goals are ambitious and on the background of 2023’s near-collapse, it can’t afford to slip up. Everything hinges on it delivering on estimates, or the next collapse could be permenant.
Final thoughts
While both these challenger banks could face some margin pressure from falling rates, their strategic positioning and operational improvements make them worth considering. In many ways, they have advantages (and buffers) that the Big Four simply can’t compete with.
For retirement-focused investors seeking diversification beyond the big players, FTSE 250 challenger banks offer a compelling alternative to think about. Whether seeking growth opportunities or steady income, the mid-cap index offers a wide variety of options.
