Authorizes income tax addition and subtraction modifications for research and experimentation costs

HB 136 modifies Missouri's income tax calculation by adding certain federal tax items to a taxpayer's federal adjusted gross income and subtracting others. It requires adding back specific federal refunds (like those tied to Missouri benefits or pandemic payments), interest on certain bonds, and excess deductions for research/property costs. It also allows subtracting items like interest on U.S. obligations, basis differences for property, and military combat zone income. These changes directly affect Missouri taxpayers filing state returns, altering their taxable income based on federal tax outcomes.