We have two classes of common stock, which we refer to as our Class A common stock and our Class B common stock. Our certificate of incorporation provides that whenever our board of directors declares a dividend on our Class B common stock, our board of directors shall simultaneously declare a dividend on our Class A common stock that is payable to the holders of our Class A common stock at the same time and as of the same record date at a rate that is at least 10% greater than the rate at which our board of directors declared a dividend on our Class B common stock. Accordingly, we use the two-class method to compute our earnings per common share. The two-class method is an earnings allocation formula that determines earnings per share separately for each class of common stock based on dividends we have declared and an allocation of our remaining undistributed earnings using a participation percentage that reflects the dividend rights of each class. The table below presents for the periods indicated a reconciliation of the numerators and denominators we used to compute basic and diluted net income per share for our Class A common stock and our Class B common stock:

 

In order to write automobile insurance in the state of Michigan, MICO is required to be a member of the Michigan Catastrophic Claims Association (“MCCA”).  The MCCA provides reinsurance to MICO for personal automobile and commercial automobile personal injury claims in the state of Michigan over a set retention. In November 2021, the MCCA approved the return of approximately $3.0 billion of its estimated surplus to its member insurance companies and provided guidance to those companies with respect to the payment of refunds to Michigan policyholders in the first half of 2022. We recorded a receivable from the MCCA and a corresponding payable for cash refunds due to Michigan policyholders in the amount of $18.1 million on our balance sheet as of December 31, 2021. In March 2022, we received such payment from the MCCA and subsequently paid the refunds due to our Michigan policyholders.

At March 31, 2022, our holdings of obligations of states and political subdivisions included general obligation bonds with an aggregate fair value of $283.6 million and an amortized cost of $296.1 million. Our holdings at March 31, 2022 also included special revenue bonds with an aggregate fair value of $152.9 million and an amortized cost of $157.5 million. With respect to both categories of those bonds at March 31, 2022, we held no securities of any issuer that comprised more than 10% of our holdings of either bond category. Education bonds and water and sewer utility bonds represented 48% and 35%, respectively, of our total investments in special revenue bonds based on the carrying values of these investments at March 31, 2022. Many of the issuers of the special revenue bonds we held at March 31, 2022 have the authority to impose ad valorem taxes. In that respect, many of the special revenue bonds we held at March 31, 2022 are similar to general obligation bonds.

 

At December 31, 2021, our holdings of obligations of states and political subdivisions included general obligation bonds with an aggregate fair value of $284.9 million and an amortized cost of $272.7 million. Our holdings also included special revenue bonds with an aggregate fair value of $160.8 million and an amortized cost of $154.2 million. With respect to both categories of bonds, we held no securities of any issuer that comprised more than 10% of that category at December 31, 2021. Education bonds and water and sewer utility bonds represented 48% and 35%, respectively, of our total investments in special revenue bonds based on their carrying values at December 31, 2021. Many of the issuers of the special revenue bonds we held at December 31, 2021 have the authority to impose ad valorem taxes. In that respect, many of the special revenue bonds we held are similar to general obligation bonds.

We have segregated within accumulated other comprehensive (loss) income the net unrealized losses of $15.1 million arising prior to the November 30, 2013 reclassification date for fixed maturities reclassified from available for sale to held to maturity. We are amortizing this balance over the remaining life of the related securities as an adjustment of yield in a manner consistent with the accretion of discount on the same fixed maturities. We recorded amortization of $ 149,475 and $371,265 in other comprehensive loss during the three months ended March 31, 2022 and 2021, respectively. At March 31, 2022 and December 31, 2021, net unrealized losses of $5.0 million and $5.2 million, respectively, remained within accumulated other comprehensive (loss) income.

 

We make estimates concerning the valuation of our investments and the recognition of other-than-temporary declines in the value of our investments. For equity securities, we measure investments at fair value, and we recognize changes in fair value in our results of operations. With respect to a debt security that is in an unrealized loss position, we first assess if we intend to sell the debt security. If we determine we intend to sell the debt security, we recognize the impairment loss in our results of operations. If we do not intend to sell the debt security, we determine whether it is more likely than not that we will be required to sell the debt security prior to recovery. If we determine it is more likely than not that we will be required to sell the debt security prior to recovery, we recognize the impairment loss in our results of operations. If we determine it is more likely than not that we will not be required to sell the debt security prior to recovery, we then evaluate whether a credit loss has occurred with respect to that security. We determine whether a credit loss has occurred by comparing the amortized cost of the debt security to the present value of the cash flows we expect to collect. If we expect a cash flow shortfall, we consider that a credit loss has occurred. If we determine that a credit loss has occurred, we consider the impairment to be other than temporary. We then recognize the amount of the impairment loss related to the credit loss in our results of operations, and we recognize the remaining portion of the impairment loss in our other comprehensive income, net of applicable taxes. In addition, we may write down securities in an unrealized loss position based on a number of other factors, including when the fair value of an investment is significantly below its cost, when the financial condition of the issuer of a security has deteriorated, the occurrence of industry, issuer or geographic events that have negatively impacted the value of a security and rating agency downgrades. We held 593 debt securities that were in an unrealized loss position at March 31, 2022. Based upon our analysis of general market conditions and underlying factors impacting these debt securities, we considered these declines in value to be temporary.

We amortize premiums and discounts on debt securities over the life of the security as an adjustment to yield using the effective interest method. We compute realized investment gains and losses using the specific identification method.

We amortize premiums and discounts on mortgage-backed debt securities using anticipated prepayments.

We evaluate the performance of our personal lines and commercial lines segments based upon the underwriting results of our insurance subsidiaries using statutory accounting principles (“SAP”) that various state insurance departments prescribe or permit. Our management uses SAP to measure the performance of our insurance subsidiaries instead of United States generally accepted accounting principles (“GAAP”). SAP financial measures are considered non-GAAP financial measures under applicable SEC rules because they include or exclude certain items that the most comparable GAAP financial measures do not ordinarily include or exclude.