Paul Frenkiel
Analyst · William Wallace with Raymond James
Thank you, Damian. Return on assets and equity for the third quarter were, respectively, 1.8% and 18% compared to 1.5% and 17% in Q3 2020. The increased returns reflected a $2.2 million increase in noninterest income, a $2.6 million decrease in noninterest expense, and a lower tax rate. A $900,000 increase in net interest income reflected loan growth but was significantly offset by the $1.9 million impact of prepayments on commercial real estate loans. However, net realized and unrealized gains on commercial loans increased $3.6 million, which resulted primarily from fees related to those prepayments.
In the third quarter of 2021, we recommenced the origination of such loans, which are intended to offset the impact of such prepayments and payoffs.
Interest income reflected a reduction of $1 million in security interest, reflecting lower securities balances, prepayments of higher-yielding securities and lower reinvestment rates. Our average loans for the quarter of $4.6 billion grew 9% over Q3 2020. We believe our loan portfolios generally are lower risk than other forms of lending as a result of their charge-off history which reflects the nature of related collateral.
Our non-SBA $1.5 billion of commercial real estate loans at fair value are comprised primarily of apartment buildings, while our SBLOC and IBLOC portfolios are respectively collateralized by marketable securities or the cash value of life insurance. Our small business loan portfolios comprised primarily of SBA loans, which are either 75% government-guaranteed or have 50% to 60% origination date loan to values. For our leasing portfolio, we have recourse to underlying vehicles in a prolonged history of pricing leases to minimize losses.
Tables contained in the earnings press release detail the diversification of our loan portfolios. Substantially, all loans with COVID payment deferrals have recommenced payments and only $1.3 million of non-U.S. government-guaranteed principal remained in deferral at September 30.
Interest expense was comparable to Q3 2020, while the Q3 2021 cost of funds was 18 basis points. Most of our deposit interest expense is contractually tied to a percentage of changes in market interest rates. The net interest margin was 3.35% compared to 3.37% in Q3 2020. While yields on loans were lower at 4.05% compared to 4.22%, they comprised a greater proportion of interest-earning assets in 2021, which contributed positively to the 2021 margin.
The Q2 2023 NIM of 3.19% reflected the impact of 2021 stimulus payments, which temporarily increased balances at the Federal Reserve earning nominal rates. As recipients spent their stimulus, average interest-earning assets were reduced from $6.8 billion last quarter to $6.1 billion this quarter.
The provision for credit losses increased to $1.6 million, which reflected the impact of the charge-off of the nonguaranteed portion of an SBA loan on the CECL methodology as well as loan growth. Because SBLOC and IBLOC loans are respectively collateralized by marketable securities and the cash value of life insurance, and have incurred only nominal credit losses, management excludes those loans from the ratio of the allowance to total loans in its internal analysis. The adjusted ratio was approximately 1.2%.
Prepaid debit and other payment related accounts are our largest funding source and the primary driver of noninterest income. Total fees and related payments income decreased 5% to $20.1 million in Q3 2021 compared to the prior year, reflecting the exit of the single relationship Damian mentioned previously. Noninterest expense for Q3 2021 was $39.4 million, reflecting a decrease of $2.6 million or 6% from the prior year. The decrease reflected a $1.9 million decrease in FDIC insurance, which reflected the lower insurance rate noted earlier in the call. While the future impact may be $1 million per quarter, the current quarter impact was higher due to the cumulative effect of the change.
Multiple factors are considered in the FDIC insurance assessments, which also may be modified by the FDIC in the future. We continue to focus on expense management, especially in relation to revenue growth. Third quarter results also reflected the impact of an approximate 23% tax rate versus higher tax rates in recent years. The reduction resulted from excess tax deductions related to stock-based compensation. The large deductions and tax benefit resulted from the increase in the company's stock price as compared to the original grant date of the stock compensation.
Book value per share increased 15% to $11.13, compared to $9.71 a year earlier, reflecting earnings per share and the impact of stock repurchases. I will now turn the call back to Damian.