Three Months Ended December 31, 2022 Compared to the Three Months Ended December 30, 2021
Net sales. Net sales were $6,516,256 for the three months ended December 31, 2022 compared to $6,695,778 for the three months ended December 31, 2021, a slight decrease of 2.7% . Product sales decreased by $522,126, EDC sales increased $366,899, Customer Repair revenue saw a modest decrease of $24,295 for the three months ended December 31, 2022. The increase in EDC sales was driven by two new Research & Development projects. The decrease in product sales was a function of lower aftermarket sales orders to commercial air transport customers . The sales decrease was partially offset by an increase in the OEM business, in which demand remained strong during Q1.
Cost of sales. Cost of sales increased $64,395, or 2.4%, to $2,792,452, or 42.9% of net sales, in the three months ended December 31, 2022, compared to $2,728,057 or 40.7% of net sales, in the three months ended December 31, 2021. The increase in cost of sales was primarily the result of slightly higher direct material costs. The Company’s overall gross margin was 57.1% and 59.3% for the three months ended December 31, 2022 and 2021, respectively.
Research and development. R&D expense decreased $66,080, or 9.0%, to $670,445 in the three months ended December 31, 2022 from $736,740 in the three months ended December 31, 2021. As a percentage of net sales, R&D expense decreased to 10.3% of net sales in the three months ended December 31, 20221 from 11.0% of net sales in the three months ended December 31, 2021. The decrease in R&D expense in the quarter was primarily the result of $57,406 of R&D expense being moved to Cost of Sales related to the EDC sales. Total R&D with the EDC related labor costs amounted to $727,851, which is 11.2% and comparable to R&D as a percent to sales in prior year.
Selling, general and administrative. Selling, general and administrative expense increased by $454,881 to $2,261,863 in the three months ended December 31, 2022 from $1,806,982 in the three months ended December 31, 2021. As a percentage of net sales, selling, general and administrative expenses increased to 34.7% of net sales in the three months ended December 31, 2022 from 27.0% of net sales in the three months ended December 31, 2021. The increase in selling, general and administrative expense in the quarter was primarily the result of an increase in non-cash long-term incentive compensation, professional & legal fees, and employee relocation costs.
Interest income. Interest income increased by $115,796 to $115,892 in the three months ended December 31, 2022 from $96 in the three months ended December 31, 2021, mainly a result of increased cash on the balance sheet, increased interest rates and re-allocating funds into higher yielding investments compared to the same period in the prior year.
Other income. Other income is mainly composed of royalties earned and increased by $1,957 to $18,196 in the three months ended December 31, 2022 compared to the same period in the prior year.
Income tax expense. The income tax expense for the three months ended December 31, 2022 was $226,933 as compared to an income tax expense of $307,490 for the three months ended December 31, 2021.
The effective tax rate for the three months ended December 31, 2022 was 24.5%, compared to 21.3% for the three months ending December 31, 2021.
Net income. The Company reported net income for the three months ended December 31, 2022 of $698,651 compared to net income of $1,133,058 for the three months ended December 31, 2021. On a diluted basis, the net income per share was $0.04 for the three months ended December 31, 2022 compared to net income per share of $0.07 for the three months ended December 31, 2021.