4. Income Taxes

Effective tax rates for the thirteen and thirty-nine weeks ended September 26, 2019 and September 27, 2018 were based on the Company’s forecasted annualized effective tax rates and were adjusted for discrete items, such as stock option exercises, that occurred within each period. Our effective income tax rates were (39.3)% and 17.1% for the thirteen weeks ended September 26, 2019 and September 27, 2018, respectively. The lower effective tax rate for the current period was primarily due to the recognition of higher excess tax benefits related to stock options exercised than in the corresponding prior year period

Our effective income tax rates were (4.9)% and 3.5% for the thirty-nine weeks ended September 26, 2019 and September 27, 2018, respectively. The lower effective tax rate for the thirty-nine weeks ended September 26, 2019 was primarily due to the recognition of higher excess tax benefits related to stock options exercised than in the corresponding prior year period.