compared to the statutory federal income tax rate for the 2018 thirteen-week period was primarily attributable to state taxes, the elimination of the performance-based compensation exception under Section 162(m) included in the Tax Reform Act and the meals and entertainment exclusion. The effective income tax rate for the 2017 thirteen-week period was lower than the statutory federal income tax rate primarily as a result of federal domestic production activities deductions and research and development credits recognized as discrete items during the thirteen-week period ended September 30, 2017, partially offset by the effect of state taxes and the meals and entertainment exclusion. The effective income tax rate in the 2018 thirteen-week period of 22.4% was lower than the 24.5% estimated annual effective income tax rate primarily due to favorable adjustments recognized during the 2018 period relating to federal domestic production activities deductions and research and development credits and excess tax benefits recognized on stock-based compensation arrangements in the 2018 period. The effective income tax rate in the 2017 thirteen-week period of 29.2% was less than the 37.8% estimated annual effective income tax rate primarily as a result of federal domestic production activities deductions and research and development credits recognized as discrete items during the thirteen-week period ended September 30, 2017, excess tax benefits recognized on stock-based compensation arrangements resulting from the Company’s adoption of ASU2016-09 during 2017 and disqualifying dispositions of the Company’s common stock by employees who obtained the stock through the exercises of incentive stock options in the 2017 period.
The net loss attributable to noncontrolling interest of $37,000 and $23,000 in the 2018 and 2017 thirteen-week periods, respectively, represents the noncontrolling investors’ share of the net loss incurred by Landstar Metro and Landstar Servicios.
Net income attributable to the Company was $66,985,000, or $1.63 per common share ($1.63 per diluted share), in the 2018 thirteen-week period. Net income attributable to the Company was $42,443,000, or $1.01 per common share ($1.01 per diluted share), in the 2017 thirteen-week period. Net income attributable to the Company was favorably impacted by the enactment of the Tax Reform Act by approximately $11,472,000, or $0.28 per common share ($0.28 per diluted share), in the 2018 thirteen-week period, as a result of the permanent reduction of the U.S. corporate income tax rate from a maximum of 35% to a flat 21%. Net income attributable to the Company was favorably impacted by the result of federal domestic production activities deductions and research and development credits of approximately $5,200,000, or $0.12 per common share ($0.12 per diluted share), in the 2017 thirteen-week period. The company does not expect significant federal domestic productions activities deductions or research and development credits in future periods.
CAPITAL RESOURCES AND LIQUIDITY
Working capital and the ratio of current assets to current liabilities were $483,961,000 and 1.9 to 1, respectively, at September 29, 2018, compared with $412,560,000 and 1.8 to 1, respectively, at December 30, 2017. Landstar has historically operated with current ratios within the range of 1.5 to 1 to 2.0 to 1. Cash provided by operating activities was $204,205,000 in the 2018 thirty-nine-week period compared with $132,264,000 in the 2017 thirty-nine-week period. The increase in cash flow provided by operating activities was primarily attributable to increased net income.
The Company declared and paid $0.465 per share, or $19,276,000 in the aggregate, in cash dividends during the thirty-nine-week period ended September 29, 2018 and, during such period, also paid $62,985,000 of dividends payable which were declared during fiscal year 2017 and included in current liabilities in the consolidated balance sheet at December 30, 2017. The Company declared and paid $0.28 per share, or $11,739,000 in the aggregate, in cash dividends during the thirty-nine-week period ended September 30, 2017. During the thirty-nine-week period ended September 29, 2018, the Company purchased 1,000,000 shares of its common stock at a total cost of $105,488,000. During the thirty-nine-week period ended September 30, 2017, the Company did not purchase any shares of its common stock. As of September 29, 2018, the Company may purchase up to an additional 2,000,000 shares of its common stock under its authorized stock purchase programs. Long-term debt, including current maturities, was $113,847,000 at September 29, 2018, $11,266,000 lower than at December 30, 2017.
Equity was $726,210,000, or 86% of total capitalization (defined as long-term debt including current maturities plus equity), at September 29, 2018, compared to $653,877,000, or 84% of total capitalization, at December 30, 2017. The increase in equity was primarily a result of net income, partially offset by purchases of shares of the Company’s common stock and dividends declared by the Company in the 2018 thirty-nine-week period.
On June 2, 2016, Landstar entered into a credit agreement with a syndicate of banks and JPMorgan Chase Bank, N.A., as administrative agent (the “Credit Agreement”). The Credit Agreement, which matures on June 2, 2021, provides $250,000,000 of borrowing capacity in the form of a revolving credit facility, $50,000,000 of which may be utilized in the form of letter of credit guarantees. The Credit Agreement includes an “accordion” feature providing for a possible increase up to an aggregate borrowing amount of $400,000,000. The Company’s prior credit agreement was terminated on June 2, 2016.
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