(This measure has not been amended since it was introduced. The expanded summary of the House reported version is repeated here.) Investing in Main Street Act of 2017 (Sec. 2) This bill amends the Small Business Investment Act of 1958 to increase from 5% to 15% of its capital and surplus, the amount a national bank, a member bank of the Federal Reserve System, a nonmember insured bank (to the extent permitted under applicable state law), or a federal savings association may invest in one or more small business investment companies (SBICs), or in any entity established to invest solely in SBICs. The increase is subject to the approval of the appropriate federal banking agency.