We have four reportable segments across our two business platforms, Optum and UnitedHealthcare:
The ongoing Medicare Advantage funding pressure places continued importance on effective medical management and ongoing improvements in administrative efficiency. There are a number of adjustments we have made to partially offset these rate pressures and reductions. In some years, these adjustments impact the majority of the seniors we serve through Medicare Advantage. For example, we seek to intensify our medical and operating cost management, make changes to the size and composition of our care provider networks, adjust members' benefits and implement or increase the member premiums supplementing the monthly payments we receive from the government. Additionally, we decide annually on a county-by-county basis where we will offer Medicare Advantage plans.
Our available-for-sale debt portfolio had a weighted-average duration of 3.7 years and a weighted-average credit rating of “Double A” as of December 31, 2020. When multiple credit ratings are available for an individual security, the average of the available ratings is used to determine the weighted-average credit rating.
Short-Term Borrowings. Our revolving bank credit facilities provide liquidity support for our commercial paper borrowing program, which facilitates the private placement of senior unsecured debt through independent broker-dealers, and are available for general corporate purposes. For more information on our commercial paper and bank credit facilities, see Note 8 of the Notes to the Consolidated Financial Statements included in Part II, Item 8, “Financial Statements.”
-Performing an overlay of the historical claims data used in management’s current year model to the data used in prior periods to validate that there were no material changes to the claims data tested in prior periods.
-Developing an independent estimate of the IBNR claim liability and comparing our estimate to management’s estimate.
The Company’s pharmacy care services businesses contract with pharmaceutical manufacturers, some of which provide rebates based on use of the manufacturers’ products by its affiliated and non-affiliated clients. The Company accrues rebates as they are earned by its clients on a monthly basis based on the terms of the applicable contracts, historical data and current estimates. The pharmacy care services businesses bill these rebates to the manufacturers on a monthly or quarterly basis depending on the contractual terms and record rebates attributable to affiliated clients as a reduction to medical costs. The Company generally receives rebates two to five months after billing. As of December 31, 2020 and 2019, total pharmaceutical manufacturer rebates receivable included in other receivables in the Consolidated Balance Sheets amounted to $6.3 billion and $4.7 billion, respectively.
The Company’s unrealized losses from all securities as of December 31, 2020 were generated from approximately 2,000 positions out of a total of 36,000 positions. The Company believes it will collect the timely principal and interest due on its debt securities having an amortized cost in excess of fair value. The unrealized losses were primarily caused by interest rate increases and not by unfavorable changes in the credit quality associated with these securities which impacted the Company’s assessment on collectability of principal and interest. At each reporting period, the Company evaluates available-for-sale debt securities for any credit-related impairment when the fair value of the investment is less than its amortized cost. The Company evaluated the expected cash flows, the underlying credit quality and credit ratings of the issuers, and the potential economic impacts of COVID-19 on the issuers, noting no significant credit deterioration since purchase. As of December 31, 2020, the Company did not have the intent to sell any of the securities in an unrealized loss position. Therefore, the Company believes these losses to be temporary. The allowance for credit losses on available-for-sale debt securities at December 31, 2020 was not material.
Under its Board of Directors’ authorization, the Company maintains a share repurchase program. The objectives of the share repurchase program are to optimize the Company’s capital structure and cost of capital, thereby improving returns to shareholders, as well as to offset the dilutive impact of share-based awards. Repurchases may be made from time to time in open market purchases or other types of transactions (including prepaid or structured share repurchase programs), subject to certain Board restrictions. In June 2018, the Board renewed the Company’s share repurchase program with an authorization to repurchase up to 100 million shares of its common stock.
Stock option activity for the year ended December 31, 2020 is summarized in the table below:
The following is a description of the types of products and services from which each of the Company’s four reportable segments derives its revenues: