Commercial real estate loans, excluding owner-occupied non-farm, non-residential loans, were 246.0% of total risk-based capital at March 31, 2021, as compared to 234.0% at December 31, 2020. Construction and land development loans were 57.0% of total risk-based capital at March 31, 2021, as compared to 47.7% at December 31, 2020.
At March 31, 2021, real estate mortgage loans included home equity loans of $32.5 million and residential real estate loans of $199.9 million, compared to $34.2 million and $199.3 million at December 31, 2020, respectively. Home equity loans decreased $1.7 million, or 5.0%, during the three months ended March 31, 2021, while residential real estate loans increased $515 thousand, or 0.3%, during the three months ended March 31, 2021. At March 31, 2021, commercial loans were $168.3 million, compared to $152.8 million at December 31, 2020, an increase of $15.5 million, or 10.2%, during the three months ended March 31, 2021.
The overall increase in loans from the year ended December 31, 2020 to March 31, 2021 was due primarily to the origination and funding of approximately $26.2 million in loans under round two of the PPP, which was partially offset by forgiveness payments received of approximately $17.5 million under round one of the PPP, and an increase in organic growth, including growth of approximately $12.2 million in loans related to Virginia Partners recent expansion into the Greater Washington market. As of March 31, 2021, approximately $51.0 million in loans under rounds one and two of the PPP were still outstanding.
Beginning late in the first quarter of 2020, both Delmarva and Virginia Partners began assisting their customers in obtaining loans under the PPP in order to further assist their communities. Delmarva has provided access for customers and noncustomers to the program, allowing individuals or businesses visiting their website to access the SBA loan application and complete the process through a third party vendor. Loans processed through Delmarva’s website are funded by other banks or outside funding sources. During round one of this program, Virginia Partners, an SBA approved lender, directly originated and funded almost 700 loans totaling approximately $64.2 million, all of which were previously pledged as collateral to the Federal Reserve Bank Discount Window under the PPP Liquidity Facility. Beginning in the fourth quarter of 2020 and continuing through the first quarter of 2021, Virginia Partners received forgiveness payments from the SBA related to many of these loans. As of March 31, 2021, Virginia Partners had approximately $24.8 million in loans still outstanding under round one of this program, none of which have been pledged as collateral to the Federal Reserve Bank Discount Window under the PPP Liquidity Facility. Remaining aggregate fees, net of costs to originate, from the SBA of approximately $549 thousand will continue to be recognized in interest income over the life of these loans. Upon forgiveness of these loans, the remaining aggregate fees, net of costs to originate, will be recognized in interest income on an accelerated basis, which Virginia Partners expects to continue through 2021. Beginning early in the first quarter of 2021, both Delmarva and Virginia Partners began assisting their customers in obtaining loans under round two of this program in an identical manner as was done by each under round one of the program. As of March 31, 2021, Virginia Partners has directly originated and funded over 330 loans totaling approximately $26.2 million, none of which have been pledged as collateral to the Federal Reserve Bank Discount Window under the PPP Liquidity Facility. Aggregate fees, net of costs to originate, from the SBA of approximately $1.2 million will be recognized in interest income over the life of these loans. Upon forgiveness of these loans, the remaining aggregate fees, net of costs to originate, will be recognized in interest income on an accelerated basis.
Investment Securities. The investment securities portfolio is a significant component of the Company's total interest-earning assets. Total investment securities averaged $129.3 million during the three months ended March 31, 2021 as compared to $113.9 million for the three months ended March 31, 2020. This represented 8.8% and 9.4% of total average interest-earning assets for the three months ended March 31, 2021 and 2020, respectively. This increase was primarily due to management of the investment securities portfolio in light of the Company’s liquidity needs, which was partially offset by accelerated prepayments on mortgage-backed investment securities in the low interest rate environment.
The Company classifies all of its investment securities as available for sale. This classification requires that investment securities be recorded at their fair value with any difference between the fair value and amortized cost (the purchase price adjusted by any discount accretion or premium amortization) reported as a component of stockholders’ equity (accumulated other comprehensive income), net of deferred taxes. At March 31, 2021 and December 31, 2020, investment securities available for sale, at fair value totaled $118.0 million and $124.9 million, respectively. Investment securities available for sale, at fair value decreased by $6.9 million, or 5.5%, during the three months ended March 31, 2021. This decrease was primarily due to higher yielding investment securities being called, accelerated prepayments on