Bank deposit rates in the US have reached the highest levels in 15 years, benefiting savers but posing challenges for lenders. The increased competition among banks to attract and retain depositors has pushed savings account rates to 5.05%, the highest since February 2008. These higher funding costs are eating into lenders' profitability, measured by the net interest margin, which is the difference between the interest earned from loans and the interest paid on deposits. This will likely hurt second-quarter results, particularly for mid-sized regional banks that faced difficulties in the previous year. Larger US banks such as JPMorgan Chase, Wells Fargo, and Bank of America are expected to demonstrate resilience and diversity in their earnings reports, benefiting from higher loan rates and additional revenue streams. Banks more reliant on investment banking, like Goldman Sachs, may face difficulties due to a recent decline in deal-making.