The American Innovation and Jobs Act seeks to significantly enhance tax benefits for businesses engaged in research and development. A primary provision of the bill is the restoration of immediate expensing for research and experimental expenditures, allowing taxpayers to deduct these costs in the year they are paid or incurred. This change amends Section 174 of the Internal Revenue Code and applies to amounts paid or incurred in taxable years beginning after December 31, 2021, reversing a previous requirement to amortize these expenses over five years. Furthermore, the bill expands the refundable research credit specifically for new and small businesses. It gradually increases the maximum refundable credit cap from $250,000 to $750,000 by 2034. The eligibility period for this credit is also extended from five to eight taxable years for startups, and the gross receipts test is modified, raising the maximum gross receipts threshold from $5 million to $15 million and adjusting the 'no gross receipts' rule. These changes to the refundable credit are effective for taxable years beginning after December 31, 2024. Finally, the legislation aims to increase access to the research credit for startups by introducing special rules for qualified small businesses. These rules include increasing the alternative simplified credit rate from 14 percent to 20 percent. Startups can also elect to apply a 10 percent rate for the alternative incremental credit or disregard taxable years with no qualified research expenses when calculating their average. These provisions are effective for taxable years beginning after the date of the Act's enactment.