per common share was $29.70 at March 31, 2022, compared to $30.75 at December 31, 2021, and $28.90 at March 31, 2021.
The Bank is well capitalized under the minimum capital requirements established by the Federal Deposit Insurance Corporation at March 31, 2022, with a CBLR of 12.2%, compared to the normally required CBLR of greater than 9.0%. The Company’s Tier 1 leverage-based ratio was 10.8% at March 31, 2022.
Credit Quality
The ACLL at March 31, 2022, decreased to $23.4 million, or 1.28% of gross loans receivable, excluding loans HFS, compared to $25.6 million, or 1.46% of gross loans receivable, excluding loans HFS at December 31, 2021, and decreased from $27.4 million, or 1.69% of gross loans receivable, excluding loans HFS, at March 31, 2021. Nonperforming loans increased $968,000 to $6.8 million at March 31, 2022, from $5.8 million at December 31, 2021, and decreased $2.5 million from $9.3 million at March 31, 2021. The year over year decrease in the ACLL was primarily due to the one-time cumulative-effect adjustment of $2.9 million as of the CECL adoption date. The reserve for unfunded commitments increased $2.6 million to $3.1 million at March 31, 2022, compared to $499,000 at December 31, 2021, and increased from $398,000 at March 31, 2021, primarily due to the one-time cumulative-effect adjustment of $2.4 million as of the CECL adoption date and increases in unfunded commitments over the period.
Loans classified as substandard decreased $5.0 million to $13.1 million at March 31, 2022, compared to $18.1 million at December 31, 2021, and decreased $7.8 million from $20.9 million at March 31, 2021. The quarter over linked quarter decrease in substandard loans was attributable to decreases of $2.3 million in commercial and industrial loans, $1.7 million in one-to-four-family loans, and $916,000 in commercial real estate loans. The year over year decrease in substandard loans was primarily due to decreases of $6.2 million in one-to-four-family loans, $1.9 million in construction and development loans, and $934,000 in commercial real estate loans, partially offset by a $1.6 million increase in commercial and industrial loans. There were no other real estate owned (“OREO”) properties at March 31, 2022, December 31, 2021, or March 31, 2021.
Operating Results
Net interest income increased $2.6 million, to $22.7 million for the three months ended March 31, 2022, from $20.1 million for the three months ended March 31, 2021. This comparable quarter over quarter increase was primarily the result of an improved mix of loans versus other interest-bearing assets and increased balances in higher yielding loans funded by lower cost deposits. Interest income increased $1.8 million, primarily due to an increase of $1.5 million in interest income on loans receivable, including fees, impacted primarily by loan growth and net deferred fees recognized upon SBA forgiveness of PPP loans. Interest expense decreased $780,000, primarily as a result of repricing deposit rates and a reduction in higher cost borrowings. For the three months ended March 31, 2022, the total recognition of net deferred fees on forgiven and amortizing PPP loans was $264,000, as compared to $653,000 for the three months ended March 31, 2021.
NIM increased 25 basis points to 4.24% for the three months ended March 31, 2022, from 3.99% for the same period in the prior year. The comparable quarter over quarter increase in NIM was impacted by an improved mix of interest-bearing assets, including a higher balance of higher yielding portfolio loans and investment securities and a significant decrease of interest-bearing cash balances earning a nominal yield combined with declining deposit and borrowing costs.