Unrealized Gain on Securities

  
  
(d) The Loan under the fair value option is included in Other investments in the condensed consolidated balance sheets.   
(e) Available-for-sale investments are included in Short-term investments in the condensed consolidated balance sheets.  
(f) Forward foreign exchange contracts in an asset position are included in Other current assets in the condensed consolidated balance sheets.  
(g) Forward foreign exchange contracts in a liability position are included in Other current liabilities in the condensed consolidated balance sheets.  
Level 1 Fair Value Measurements  
As of March 31, 2022, we own 12,987,900 ordinary voting shares and 9,588,908 preference shares of Sartorius AG (Sartorius), of Goettingen, Germany, a process technology supplier to the biotechnology, pharmaceutical, chemical and food and beverage industries. We own approximately 37% of the ordinary outstanding shares (excluding treasury shares) and 28% of the preference shares of Sartorius as of March 31, 2022. The Sartorius family trust (Sartorius family members are beneficiaries of the trust) holds a majority interest of the outstanding ordinary shares of Sartorius. We do not have the ability to exercise significant influence over the operating and financial policies of Sartorius primarily because we do not have any representative or designee on Sartorius' board of directors and have tried and failed to obtain access to operating or financial information necessary to apply the equity method of accounting.  
The changes in fair market value of our investment in Sartorius for the three months ended March 31, 2022 was $4.45 billion loss and is recorded in our condensed consolidated statements of income (loss).  
Level 2 Fair Value Measurements  
To estimate the fair value of Level 2 debt securities as of March 31, 2022, our primary pricing provider uses Refinitiv as the primary pricing source. Our pricing process allows us to select a hierarchy of pricing sources for securities held. If Refinitiv does not price a Level 2 security that we hold, then the pricing provider will utilize our custodian supplied pricing as the secondary pricing source.   
Available-for-sale investments consist of the following (in millions):

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
|   | March 31, 2022 |
|  | AmortizedCost |  | UnrealizedGains |  | UnrealizedLosses |  | Allowances for Credit Losses | FairValue |
| Short-term investments: |   |  |   |  |   |  |  |   |
| Corporate debt securities | $ | 579.1  |  |  | $ | 0.2  |  |  | $ | (2.6) |  |  | $ | —  |  | $ | 576.7  |  |
| Municipal obligations | 34.8  |  |  | —  |  |  | (0.1) |  |  | —  |  | 34.7  |  |
| Asset-backed securities | $ | 331.9  |  |  | $ | 0.1  |  |  | $ | (1.6) |  |  | $ | —  |  | $ | 330.4  |  |
| U.S. government sponsored agencies | 255.2  |  |  | —  |  |  | (0.9) |  |  | —  |  | 254.3  |  |
| Foreign government obligations | $ | 1.5  |  |  | $ | —  |  |  | $ | —  |  |  | $ | —  |  | $ | 1.5  |  |
| Certificates of Deposit | 8.0  |  |  | —  |  |  | —  |  |  | —  |  | 8.0  |  |
|  |  |  |  |  |  |  |  |  |
|   | $ | 1,210.5  |  |  | $ | 0.3  |  |  | $ | (5.2) |  |  | $ | —  |  | $ | 1,205.6  |  |
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The following is a summary of the amortized cost and estimated fair value of our debt securities at March 31, 2022 by contractual maturity date (in millions):17
