decreased the average selling price per pound by approximately $4.43, partially offset by higher market prices of raw materials, which increased average selling price per pound by approximately $1.93.
Cost of Sales. Cost of sales was $78.6 million, or 82.5% of net revenues, in the fourth quarter of fiscal 2021 compared to $76.0 million, or 95.0% of net revenues, in the same period of fiscal 2020. The decrease was primarily due to a lower-value product mix, the Company’s actions taken to lower costs and a lower amount of fixed costs that were required to be directly expensed, partially offset by higher shipped volumes.
Gross Profit. As a result of the above factors, gross profit was $16.7 million for the fourth quarter of fiscal 2021, an increase of $12.7 million from the same period of fiscal 2020. Gross profit as a percentage of net revenue increased to 17.5% in the fourth quarter of fiscal 2021 as compared to 4.9% in the same period of fiscal 2020. The fourth quarter of fiscal 2020 was adversely impacted by the COVID-19 pandemic as volumes reduced significantly.
Selling, General and Administrative Expense. Selling, general and administrative expense was $11.0 million for the fourth quarter of fiscal 2021, an increase of $2.8 million, or 34.4%, from the same period of fiscal 2020. Selling, general and administrative expense as a percentage of net revenues increased to 11.6% for the fourth quarter of fiscal 2021 compared to 10.2% for the same period of fiscal 2020. Higher incentive compensation expense was the primary driver of the increased expense in comparison to the fourth quarter of fiscal 2020. Additionally, bank fees associated with the credit facility entered into this fiscal year were higher in the fourth quarter of fiscal 2021 as compared to the same period of fiscal 2020.
Research and Technical Expense. Research and technical expense was $0.9 million, or 1.0% of net revenue, for the fourth quarter of fiscal 2021, compared to $0.9 million, or 1.2% of net revenue, in the same period of fiscal 2020.
Operating Income/(Loss). As a result of the above factors, operating income in the fourth quarter of fiscal 2021 was $4.8 million compared to operating loss of $(5.2) million in the same period of fiscal 2020.
Nonoperating retirement benefit expense. Nonoperating retirement benefit expense was $0.4 million in the fourth quarter of fiscal 2021 compared to $1.7 million in the same period of fiscal 2020. The decrease in expense was primarily driven by favorable retiree health care spending and higher-than-expected return on plan assets.
Income Taxes. Income tax expense was $1.5 million in the fourth quarter of fiscal 2021, a difference of $3.1 million from an income tax benefit of $1.5 million in the fourth quarter of fiscal 2020. This difference was driven primarily by a difference in income (loss) before income taxes of $11.4 million along with a tax rate change in the United Kingdom that resulted in an increase to income tax expense of approximately $0.4 million.
Net Income/(Loss). As a result of the above factors, net income in the fourth quarter of fiscal 2021 was $2.6 million, compared to net loss of $(5.7) million in the same period of fiscal 2020.
Fiscal Year Results
Net Revenues. Net revenues were $337.7 million in fiscal 2021, a decrease of 11.3% from $380.5 million in fiscal 2020. Volume was 14.0 million pounds in fiscal 2021, a decrease of 4.5% from 14.7 million pounds in fiscal 2020, with decreases in aerospace and chemical processing, partially offset by increases in industrial gas turbine and other markets. The decrease in volume is primarily caused by COVID-19 and issues in the aerospace supply chain due to the 737 MAX, partially offset by increased volumes in the industrial gas turbine and flue gas desulphurization markets. The product average selling price was $22.56 per pound in fiscal 2021, a decrease of 7.3%, or $1.77, from $24.33 per pound in fiscal 2020. The product average selling price per pound decreased as a result of a lower-value product mix and other pricing considerations (such as customer mix, timing of customer agreement adjustors, etc.) as compared to fiscal 2020, which decreased the product average selling price per pound by approximately $3.02, partially offset by higher raw material market prices, which increased average selling price per pound by approximately $1.25.
Cost of Sales. Cost of sales was $297.9 million, or 88.2% of net revenues, in fiscal 2021 compared to $335.9 million, or 88.3% of net revenues, in fiscal 2020. This decrease was primarily due to lower volumes sold combined with continued traction in the Company’s cost reduction initiatives, partially offset by lower fixed-cost absorption.
Gross Profit. As a result of the above factors, gross profit was $39.7 million in fiscal 2021, a decrease of $4.9 million from $44.6 million in fiscal 2020. Gross profit as a percentage of net revenue increased to 11.8% in fiscal 2021 as compared to