Sales for the second quarter of 2018 increased 0.9% to $1,264.4 million, compared to $1,252.9 million for the second quarter of 2017, with 1.3% organic growth and 1.0% acquisition-related growth partially offset by a negative 1.4% impact from foreign currency translation.
Operating income for the second quarter of 2018 was $199.6 million, an increase of 6.0% compared to $188.3 million for the comparable quarter of 2017. Excluding a $6.4 million non-cash accounting adjustment primarily related to the acquired finished goods inventory of the Innovia acquisition in 2017, operating income was $194.7 million for the second quarter of 2017.
Restructuring and other items of $3.6 million were reported for the second quarter of 2018 primarily related to reorganization costs associated with the 2016 acquisition of Checkpoint Systems Inc. and other acquisition related transaction costs. There was a net expense for restructuring and other items of $5.2 million in the 2017 second quarter.
Tax expense for the second quarter of 2018 was $41.4 million compared to $41.8 million in the prior year period. The effective tax rates for these two periods were 25.5% and 27.7%, respectively. The decrease in the effective tax rate compared to the prior year second quarter was primarily driven by the impact of the U.S. Tax Cuts and Jobs Act, which is expected to reduce the annual consolidated effective tax rate for 2018 by approximately 3.0%.
Net earnings were $121.1 million for the 2018 second quarter compared to $109.9 million for the 2017 second quarter. Basic and adjusted basic earnings per Class B share were $0.69 and $0.70, respectively, compared to basic and adjusted basic earnings per Class B share of $0.63 and $0.68, respectively, in the prior year second quarter.
For the six-month period ended June 30, 2018, sales, operating income and net earnings improved 7.7%, 15.3% and 21.2% to $2.5 billion, $400.2 million and $239.8 million, respectively, compared to the same six-month period in 2017. Included in the 2017 six-month period was a $15.2 million non-cash acquisition accounting adjustment to the acquired finished goods inventory from the Innovia acquisition that was expensed through cost of goods sold in the period. The 2018 six-month period included results from eight acquisitions completed since January 1, 2017, delivering acquisition related sales growth for the period of 5.7%. Organic sales growth was 2.3%, partially offset by 0.3% negative impact from foreign currency translation. For the six-month period ended June 30, 2018, basic and adjusted basic earnings per Class B share were $1.36 and $1.39, respectively, compared to basic and adjusted basic earnings per Class B share of $1.13 and $1.25, respectively, in the prior year six-month period. Foreign currency translation had a negative $0.01 per share impact on earnings.
Geoffrey T. Martin, CCL's president CEO, commented, "Home & Personal Care, and Food & Beverage markets both delivered strong sales growth, Healthcare & Specialty a modest sales gain, partly offset by a small decline at CCL Design compared to a strong prior year period. After an exceptional first quarter, expected softer sequential and comparative CCL Secure polymer bank note substrate volume cut second quarter overall CCL segment organic sales growth rate in half to 3.3%. This was entirely due to a large and highly profitable banknote launch order in the second quarter of 2017; prior year comparisons ease significantly in the coming quarter. Geographically, North America and Emerging Markets outperformed lower European results where the CCL Secure impact occurred. Overall CCL segment profitability improved in line with sales. Checkpoint's 4.7% organic sales growth included completion of technology rollout programs for two important retailers with profitability gains boosted by improved performance at our apparel labeling operations as restructuring initiatives took hold. Avery second quarter operating margins(1) improved to 23% on the mix impact of share loss in ring binders and similar adjacent product lines. Innovia results declined on protracted inflationary resin costs, operating challenges at our large U.K. plant and lower sales to the flexible packaging market. Adjusted basic earnings were $0.70 per Class B share, up modestly compared to the second quarter of 2017. "
Martin continued, "Foreign currency translation was a $0.02 per Class B share earnings headwind for the second quarter of 2018; foreign currency transaction impacts were nominal. At today's Canadian dollar exchange rates, currency translation would be a modest tailwind, if sustained, for the third quarter of 2018."
He concluded, "We finished the second quarter of 2018, with a solid balance sheet. The Company's net leverage ratio(4) was 1.84 times EBITDA(2) with $822 million cash-on-hand, including the proceeds to close the Treofan acquisition on July 2, 2018. $475 million undrawn capacity on our syndicated revolving credit facility leaves the Company well placed to continue its growth initiatives. Given the outlook and strong free cash flow expectation for 2018, the Board of Directors declared a dividend of $0.13 per Class B non-voting share and a dividend of $0.1275 per Class A voting share, payable to shareholders of record at the close of business on September 14, 2018, to be paid on September 28, 2018."