ZEELAND, Mich., July 24, 2014 (GLOBE NEWSWIRE) -- Gentex Corporation (Nasdaq:GNTX), the Zeeland, Michigan-based manufacturer of automotive automatic-dimming rearview mirrors, automotive electronics, dimmable aircraft windows, and fire protection products, today reported financial results for the second quarter ended June 30, 2014. For the second quarter of 2014, the Company's net sales were $338.4 million, up 18% compared with net sales of $287.0 million in the second quarter of 2013. The gross profit margin in the second quarter of 2014 was 39.7%, compared with a gross profit margin of 35.8% in the second quarter of 2013. The improvement in the gross profit margin is due to the impact of the HomeLink ® acquisition, improvements in product mix, and purchasing cost reductions, which were partially offset by annual customer price reductions. Net income for the second quarter of 2014 was $76.7 million, up 47% compared with net income of $52.1 million in the second quarter of 2013. Earnings per diluted share in the second quarter of 2014 were $0.52, an increase of $0.16 or 44% compared with earnings per diluted share of $0.36 in the second quarter of 2013. During the second quarter of 2014, the Company benefited from incremental research & development tax credits related to its tax return filings for calendar years 2010 through 2012 in the amount of $5.5 million. As a result, the effective tax rate in the second quarter of 2014 decreased to 27.4% and the incremental impact to earnings per diluted share for the quarter was approximately $0.04. Additionally, in the third quarter of 2014, the Company expects to complete further studies relating to the 2013 calendar year, and estimates the effective tax rate to be approximately 30.5% - 31.5% for the third quarter, based on current tax laws and the incremental benefits associated with research & development tax credits not originally included in 2013 financial results.