Secure Viable Banking Act or the SVB Act This bill increases the oversight of certain nonbank financial companies and bank holding companies by repealing Title IV of the Economic Growth, Regulatory Relief, and Consumer Protection Act (P.L. 115-174). (A nonbank financial company is a financial institution without a banking license that may be subject to supervision due to the company's size or risk profile. A bank holding company owns a controlling interest in one or more banks.) Specifically, the bill decreases from $250 billion to $50 billion the asset threshold at which enhanced prudential standards become mandatory, thereby requiring more companies to comply with these standards. These standards include stress testing, leverage limits, liquidity requirements, and resolution plan requirements (i.e., living will requirements). Under current law, the Federal Reserve has the discretion to determine the applicability of these standards to bank holding companies with assets between $100 billion and $250 billion. The bill also expands stress testing by increasing the number of board-run stress test scenarios from two to three; decreasing the asset threshold at which company-run stress tests are required from $250 billion to $10 billion; and requiring company-run stress tests to be performed annually or semiannually, depending on the amount of assets held. The bill also decreases from $50 billion to $10 billion the asset threshold for mandatory risk committees. Finally, the bill revises the supplemental leverage ratio applied to custodial banks and the asset treatment of certain municipal obligations.