As a percent of net revenue, gross profit margins were 25.2% in the quarter ended June 30, 2019 compared to 26.6% in the quarter ended June 30, 2018. Gross profit margins declined due to lower production levels.
Product engineering and development expenses were $881,000 in the quarter ended June 30, 2019, compared to $781,000 for the quarter ended June 30, 2018, due to increased headcount and compensation. Selling, general and administrative (“SG&A”) expenses increased by $292,000 to $2,471,000 in the quarter ended June 30, 2019, compared to $2,179,000 in the quarter ended June 30, 2018 as a result of increased sales headcount and travel expenses.
The Company had operating income of $1,398,000 for the quarter ended June 30, 2019 versus operating income of $3,456,000 for the quarter ended June 30, 2018. Operating margins were 7.4% for the quarter ended June 30, 2019, compared to 14.3% in the prior year. The decrease in operating margins was due to lower production volumes and increased operating expenses.
For the quarter ended June 30, 2019, interest and dividend income, net of fees, from the investment portfolio was $567,000, as compared to $399,000 in the quarter ended June 30, 2018. The increase was due to additional interest income from a significantly higher level of investments in corporate bonds and United States Treasury bills. Net realized and unrealized gains on marketable securities were $1,090,000 for the quarter ended June 30, 2019 versus net unrealized and realized losses of $(503,000) for the quarter ended June 30, 2018.
The effective income tax rate for the quarters ended June 30, 2019 and 2018 was 20.0%.
Net income for the quarter ended June 30, 2019 was $2,444,000, or $0.17 per diluted share, versus $2,682,000, or $0.18 per diluted share, for the quarter ended June 30, 2018.
Nine Months Ended June 30, 2019 versus June 30, 2018
Net revenue for the nine months ended June 30, 2019 and 2018 were $66,845,000 and $78,069,000, respectively, a decrease of 14.4%, reflecting a decline in orders from the significant increase in business in the prior year.
Gross profit margins increased to 29.3% in the nine months ended June 30, 2019 from 26.0% in the nine months ended June 30, 2018. The improved gross profit margins resulted from the Company’s cost management and operational improvements implemented over the past few years, partially offset by the impact of lower production volumes.
Product engineering and development expenses increased by $188,000 in the nine months ended June 30, 2019, compared to the nine months ended June 30, 2018, due to increased headcount. SG&A expenses decreased by $657,000 in the nine months ended June 30, 2019, compared to the nine months ended June 30, 2018. As a percentage of net revenues, SG&A expenses were 10.7% for the nine months ended June 30, 2019, compared to 10.0% in the prior nine months. The lower SG&A expenses in 2019 were due to reduced sales commissions and advertising expenses partially offset by an increase in sales headcount and related travel expenses.
The Company had operating income of $10,016,000 for the nine months ended June 30, 2019 versus operating income of $10,238,000 for the nine months ended June 30, 2018, on improved gross margins and lower SG&A expenses. Operating margins were 15.0% for the nine months ended June 30, 2019, compared to 13.1% in nine months ended June 30, 2018.
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