The main purpose of this legislation is to change the tax rules regarding mortgage insurance premiums. Specifically, it aims to increase the income limit for taxpayers who can deduct these premiums from their taxable income and to make this deduction a permanent feature of the tax code. Key provisions of the legislation include raising the income cap for the mortgage insurance premium deduction from 00,000 to $200,000 for individuals and from $50,000 to 00,000 for married couples filing separately. Additionally, it removes a clause that may have restricted access to this deduction.