Have you ever checked your bank account after receiving your Social Security payment and wondered why the deposit was smaller than expected? You’re not alone. Every month, millions of Medicare beneficiaries have their Medicare Part B premium automatically deducted from their Social Security benefits before the payment reaches their bank account. In some cases, changes to premiums, income-related adjustments, or benefit increases can make the net deposit appear different from previous months. Here is what you need to know about how Medicare Part B affects your Social Security payment.