Revenue and taxation; income tax; pensions; taxable income; exemption; effective date.

HB 1599 amends Oklahoma's tax code to adjust how taxable income is calculated for state income tax purposes. It modifies rules for deducting federal net operating losses (including carryforward periods) and adds specific methods for allocating income from property (like rents or royalties) and business activities. The bill maintains an exemption for certain pension benefits from Oklahoma income tax, as referenced in its title. This is a technical tax code revision affecting how businesses and individuals compute their Oklahoma taxable income.