Income Taxes	9 Months Ended
Sep. 29, 2013
Income Taxes	O. Income Taxes The effective tax rate for the three months ended September 29, 2013 and September 30, 2012 was 21% and 14%, respectively. The increase in Teradyne’s tax rate for the three months ended September 29, 2013 compared to the three months ended September 30, 2012, was primarily attributable to the reduction to deferred income tax benefit recognized discretely in 2012 in connection with Teradyne’s plan to repatriate the unremitted earnings of its Japanese subsidiary. The effective tax rate for the nine months ended September 29, 2013 and September 30, 2012 was 14% and 21%, respectively. The decrease in Teradyne’s tax rate for the nine months ended September 29, 2013 compared to the nine months ended September 30, 2012, was primarily the result of recognizing the tax benefit attributable to the retroactive reinstatement of the U.S. research and development credit and the mix of income by jurisdiction. The effective tax rate for the three months and nine months ended September 29, 2013 is lower than the 35% U.S. statutory federal tax rate primarily due to the research and development credit and the effect of foreign income taxed at a rate lower than the U.S. statutory rate.

Income Taxes

9 Months Ended

Sep. 29, 2013

O. Income Taxes

The effective tax rate for the three months ended September 29, 2013 and September 30, 2012 was 21% and 14%, respectively. The increase in Teradyne’s tax rate for the three months ended September 29, 2013 compared to the three months ended September 30, 2012, was primarily attributable to the reduction to deferred income tax benefit recognized discretely in 2012 in connection with Teradyne’s plan to repatriate the unremitted earnings of its Japanese subsidiary.

The effective tax rate for the nine months ended September 29, 2013 and September 30, 2012 was 14% and 21%, respectively. The decrease in Teradyne’s tax rate for the nine months ended September 29, 2013 compared to the nine months ended September 30, 2012, was primarily the result of recognizing the tax benefit attributable to the retroactive reinstatement of the U.S. research and development credit and the mix of income by jurisdiction.

The effective tax rate for the three months and nine months ended September 29, 2013 is lower than the 35% U.S. statutory federal tax rate primarily due to the research and development credit and the effect of foreign income taxed at a rate lower than the U.S. statutory rate.