|                                                                                                                                           |  |  |  |  |  |
|-------------------------------------------------------------------------------------------------------------------------------------------|--|--|--|--|--|
| UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549                                                                   |
|                                                                                                                                           |
| FORM 11-K                                                                                                                                 |
|                                                                                                                                           |
| FOR ANNUAL REPORTS OF EMPLOYEE STOCK PURCHASE, SAVINGS AND SIMILAR PLANS PURSUANT TO SECTION 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 |
|                                                                                                                                           |
|  X   ANNUAL REPORT PURSUANT TO SECTION 15(d) OF THE SECURITIESEXCHANGE ACT OF 1934                                                   |
|                                                                                                                                           |
| For the fiscal year ended December 31, 2021                                                                                               |
|                                                                                                                                           |
| OR                                                                                                                                        |
|                                                                                                                                           |
| __   TRANSITION REPORT PURSUANT TO SECTION 15(d) OF THESECURITIES EXCHANGE ACT OF 1934                                                    |
|                                                                                                                                           |
| For the transition period from _______ to _______                                                                                         |
|                                                                                                                                           |
| COMMISSION FILE NUMBER 1-3619                                                                                                             |
|                                                                                                                                           |
| A.   Full title of the plan and the address of the plan, if different from that of the issuer named below:                            |
|                                                                                                                                           |
| PFIZER SAVINGS PLAN FOR EMPLOYEES RESIDENT IN PUERTO RICO                                                                                 |
|                                                                                                                                           |
| B.   Name of issuer of the securities held pursuant to the plan and the address of its principal executive office:                    |
|                                                                                                                                           |
| PFIZER INC. 235 EAST 42ND STREET NEW YORK, NEW YORK 10017                                                                                 |

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|                                                                                                     |                     |  |  |  |  |
|-----------------------------------------------------------------------------------------------------|---------------------|--|--|--|--|
|                                                                                                     | Page                |
|                                                                                                     |                     |
| Report of Independent Registered Public Accounting Firm                                             | 1                   |
|                                                                                                     |                     |
| Financial Statements                                                                                |                     |
| Statements of Net Assets Available for Plan Benefits as of December 31, 2021 and 2020               | 2                   |
| Statement of Changes in Net Assets Available for Plan Benefits for the year ended December 31, 2021 | 3                   |
| Notes to Financial Statements                                                                       | Beginning on page 4 |
|                                                                                                     |                     |
| Supplemental Schedule*                                                                              |                     |
| Schedule H, Line 4i - Schedule of Assets (Held at End of Year)                                      | 9                   |
|                                                                                                     |                     |
| Exhibit Index                                                                                       | 10                  |
|                                                                                                     |                     |
| Signature                                                                                           | 11                  |

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|                                        |  |                    |               |  |      |               |   |               |  |  |  |  |  |  |  |  |
|----------------------------------------|--|--------------------|---------------|--|------|---------------|---|---------------|--|--|--|--|--|--|--|--|
|                                        |  | As of December 31, |               |
| (THOUSANDS OF DOLLARS)                 |  | 2021               |               |  | 2020 |               |
| Assets                                 |  |                    |               |  |      |               |
| Investments, at fair value             |  |                    |               |  |      |               |
| Pfizer Inc. common stock               |  | $                  | 114,896  |  |      |               | $ | 80,214   |  |  |
| Viatris  Inc. common stock             |  | —       |               |  |      | 4,669    |   |               |
|                                        |  |                    |               |  |      |               |
| Common/collective trust funds      |  | 371,060       |               |  |      | 330,543  |   |               |
| Mutual funds                           |  | 27,303        |               |  |      | 28,790   |   |               |
| Total investments, at fair value       |  | 513,259       |               |  |      | 444,217  |   |               |
|                                        |  |                    |               |  |      |               |
| Receivables                            |  |                    |               |  |      |               |
| Participant contributions              |  | —       |               |  |      | 42       |   |               |
| Company contributions                  |  | 1,370         |               |  |      | 7,265    |   |               |
| Notes receivable from participants     |  | 2,736         |               |  |      | 5,688    |   |               |
|                                        |  |                    |               |  |      |               |
| Interest and other                     |  | 143           |               |  |      | 184      |   |               |
| Total receivables                      |  | 4,248         |               |  |      | 13,179   |   |               |
| Total assets                           |  | 517,508       |               |  |      | 457,396  |   |               |
|                                        |  |                    |               |  |      |               |
| Liabilities                            |  |                    |               |  |      |               |
| Investment management fees payable     |  | 8             |               |  |      | 7        |   |               |
| Total liabilities                      |  | 8             |               |  |      | 7        |   |               |
| Net assets available for plan benefits |  | $                  | 517,500  |  |      |               | $ | 457,389  |  |  |

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|                                                             |  |                              |               |  |  |  |  |  |  |
|-------------------------------------------------------------|--|------------------------------|---------------|--|--|--|--|--|--|
| (THOUSANDS OF DOLLARS)                                      |  | Year Ended December 31, 2021 |               |
| Additions/(reductions) to net assets attributed to: |  |                              |               |
| Investment income                                           |  |                              |               |
| Net appreciation in investments                             |  | $                            | 87,750   |  |  |
| Pfizer Inc. common stock dividends                          |  | 3,264                   |               |  |
|                                                             |  |                              |               |
| Interest and dividend income from other investments         |  | 3,588                   |               |  |
| Total investment income                                     |  | 94,602                  |               |  |
| Interest income from notes receivable from participants     |  | 226                     |               |  |
| Less: Investment management, redemption and loan fees   |  | (143)                        |               |  |
| Net investment and interest income                          |  | 94,686                  |               |  |
|                                                             |  |                              |               |
| Contributions                                               |  |                              |               |
| Participant                                                 |  | 1,731                   |               |  |
| Company                                                     |  | 1,790                   |               |  |
| Rollovers into the Plan                                     |  | 7,086                   |               |  |
| Total contributions                                         |  | 10,608                  |               |  |
| Total additions                                             |  | 105,293                 |               |  |
|                                                             |  |                              |               |
| Deductions from net assets attributed to:               |  |                              |               |
| Benefits paid to participants                               |  | 45,182                  |               |  |
|                                                             |  |                              |               |
| Net increase                                                |  | 60,111                  |               |  |
|                                                             |  |                              |               |
| Net assets available for plan benefits                      |  |                              |               |
| Beginning of year                                           |  | 457,389                 |               |  |
| End of year                                                 |  | $                            | 517,500  |  |  |

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|                                                                                                                           |  |                                    |               |         |               |   |               |       |  |               |  |   |               |  |  |  |  |  |  |  |  |  |
|---------------------------------------------------------------------------------------------------------------------------|--|------------------------------------|---------------|---------|---------------|---|---------------|-------|--|---------------|--|---|---------------|--|--|--|--|--|--|--|--|--|
| The following tables set forth by level, within the fair value hierarchy, the Plan’s investments at fair value: |
|                                                                                                                           |  | Fair Value as of December 31, 2021 |
| (THOUSANDS OF DOLLARS)                                                                                                    |  | Level 1                            |               | Level 2 |               |   |               | Total |
| Pfizer Inc. common stock                                                                                                  |  | $                                  | 114,896  |         |               | $ | —  |       |  |               |  | $ | 114,896  |  |
|                                                                                                                           |  |                                    |               |         |               |   |               |       |
|                                                                                                                           |  |                                    |               |         |               |   |               |       |
| Common/collective trust funds                                                                                         |  | —                       |               |         | 371,060  |   |               |       |  | 371,060  |  |
| Mutual funds                                                                                                              |  | 27,303                        |               |         | —  |   |               |       |  | 27,303   |  |
| Total                                                                                                                     |  | $                                  | 142,199  |         |               | $ | 371,060  |       |  |               |  | $ | 513,259  |  |

|                                   |  |                                    |               |         |               |   |               |       |  |               |  |   |               |  |  |  |  |  |  |  |  |  |
|-----------------------------------|--|------------------------------------|---------------|---------|---------------|---|---------------|-------|--|---------------|--|---|---------------|--|--|--|--|--|--|--|--|--|
|                                   |  | Fair Value as of December 31, 2020 |
| (THOUSANDS OF DOLLARS)            |  | Level 1                            |               | Level 2 |               |   |               | Total |
| Pfizer Inc. common stock          |  | $                                  | 80,214   |         |               | $ | —  |       |  |               |  | $ | 80,214   |  |
| Viatris Inc. common stock         |  | 4,669                         |               |         | —  |   |               |       |  | 4,669    |  |
|                                   |  |                                    |               |         |               |   |               |       |
| Common/collective trust funds |  | —                       |               |         | 330,543  |   |               |       |  | 330,543  |  |
| Mutual funds                      |  | 28,790                        |               |         | —  |   |               |       |  | 28,790   |  |
| Total                             |  | $                                  | 113,674  |         |               | $ | 330,543  |       |  |               |  | $ | 444,217  |  |

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|                                                                                                                                     |  |                              |               |      |       |   |               |  |  |  |  |  |  |  |
|-------------------------------------------------------------------------------------------------------------------------------------|--|------------------------------|---------------|------|-------|---|---------------|--|--|--|--|--|--|--|
| The following is a reconciliation of net assets available for plan benefits per the financial statements to the Form 5500: |
|                                                                                                                                     |  | Year Ended December 31, |
| (THOUSANDS OF DOLLARS)                                                                                                              |  | 2021                         |               | 2020 |
| Net assets available for plan benefits per the financial statements                                                                 |  | $                            | 517,500  |      |       | $ | 457,389  |  |
| Amounts allocated to withdrawing participants                                                                                       |  | (86)                         |               |      | (35)  |   |
| Deemed distributions                                                                                                                |  | (538)                        |               |      | (574) |   |
| Net assets available for plan benefits per Form 5500                                                                           |  | $                            | 516,876  |      |       | $ | 456,780  |  |

|                                                                                                                                                  |  |                                   |              |  |  |  |  |  |  |
|--------------------------------------------------------------------------------------------------------------------------------------------------|--|-----------------------------------|--------------|--|--|--|--|--|--|
| The following is a reconciliation of benefits paid to participants, including rollovers, per the financial statements to the Form 5500: |  |
| (THOUSANDS OF DOLLARS)                                                                                                                           |  | Year Ended December 31, 2021 |
| Benefits paid to participants, including rollovers, per the financial statements                                                                 |  | $                                 | 45,182  |  |  |
| Amounts allocated to withdrawing participants and deemed distributions at end of year                                                            |  | 624                          |              |  |
| Amounts allocated to withdrawing participants and deemed distributions at beginning of year                                                      |  | (609)                             |              |  |
| Benefits paid to participants, including rollovers, per Form 5500                                                                           |  | $                                 | 45,197  |  |  |

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|                                                                |                                                       |  |                                   |  |                  |  |               |  |        |  |               |               |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
|----------------------------------------------------------------|-------------------------------------------------------|--|-----------------------------------|--|------------------|--|---------------|--|--------|--|---------------|---------------|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|--|
| PFIZER SAVINGS PLAN FOR EMPLOYEES RESIDENT IN PUERTO RICO      |
| SCHEDULE H, LINE 4i - SCHEDULE OF ASSETS (HELD AT END OF YEAR) |
| As of December 31, 2020                                        |
| (THOUSANDS OF DOLLARS)                                         |
|                                                                | Identity of Issuer, Borrower, Lessor or Similar Party |  | Description of Investment         |  | Rate of Interest |  | Maturity Date |  | Cost** |  | Current Value |
|                                                                |                                                       |  |                                   |  |                  |  |               |  |        |  |               |
| *                                                              | Pfizer Inc. Common Stock                              |  | Common stock                      |  |                  |  |               |  |        |  | $             | 114,896  |  |
|                                                                |                                                       |  |                                   |  |                  |  |               |  |        |  |               |
|                                                                |                                                       |  |                                   |  |                  |  |               |  |        |  |               |
|                                                                |                                                       |  |                                   |  |                  |  |               |  |        |  |               |
|                                                                |                                                       |  |                                   |  |                  |  |               |  |        |  |               |
|                                                                |                                                       |  |                                   |  |                  |  |               |  |        |  |               |
| *                                                              | NTGI - S&P 500 Index Fund                         |  | Collective trust fund             |  |                  |  |               |  |        |  | 74,070   |               |
| *                                                              | NTGI - Russell 2000 Small Cap Index Fund              |  | Collective trust fund             |  |                  |  |               |  |        |  | 12,191   |               |
| *                                                              | NTGI - Collective Government Short-Term               |  |                                   |  |                  |  |               |  |        |  |               |
|                                                                | Investment Fund                                       |  | Collective trust fund             |  |                  |  |               |  |        |  | 1,330    |               |
|                                                                | BlackRock Mid Cap Equity Index Fund                   |  | Collective trust fund             |  |                  |  |               |  |        |  | 22,132   |               |
|                                                                | BlackRock International Index Fund                    |  | Collective trust fund             |  |                  |  |               |  |        |  | 2,165    |               |
| *                                                              | Fidelity Large Cap Growth Fund                        |  | Collective trust fund             |  |                  |  |               |  |        |  | 68,563   |               |
|                                                                | Oppenheimer Developing Markets Fund                   |  | Collective trust fund             |  |                  |  |               |  |        |  | 4,478    |               |
|                                                                | Boston Partners Large Cap Value Fund                  |  | Collective trust fund             |  |                  |  |               |  |        |  | 7,273    |               |
|                                                                | T. Rowe Price Stable Value Common Trust Fund          |  | Collective trust fund             |  |                  |  |               |  |        |  | 71,322   |               |
|                                                                | Wellington International Research Equity ex           |  |                                   |  |                  |  |               |  |        |  |               |
|                                                                | Emerging Markets Fund                                 |  | Collective trust fund             |  |                  |  |               |  |        |  | 13,613   |               |
|                                                                | Vanguard Institutional Target Retirement Income Fund  |  | Collective trust fund             |  |                  |  |               |  |        |  | 5,876    |               |
|                                                                | Vanguard Institutional Target Retirement 2015 Fund    |  | Collective trust fund             |  |                  |  |               |  |        |  | 1,365    |               |
|                                                                | Vanguard Institutional Target Retirement 2020 Fund    |  | Collective trust fund             |  |                  |  |               |  |        |  | 15,300   |               |
|                                                                | Vanguard Institutional Target Retirement 2025 Fund    |  | Collective trust fund             |  |                  |  |               |  |        |  | 15,511   |               |
|                                                                | Vanguard Institutional Target Retirement 2030 Fund    |  | Collective trust fund             |  |                  |  |               |  |        |  | 23,700   |               |
|                                                                | Vanguard Institutional Target Retirement 2035 Fund    |  | Collective trust fund             |  |                  |  |               |  |        |  | 12,237   |               |
|                                                                | Vanguard Institutional Target Retirement 2040 Fund    |  | Collective trust fund             |  |                  |  |               |  |        |  | 12,160   |               |
|                                                                | Vanguard Institutional Target Retirement 2045 Fund    |  | Collective trust fund             |  |                  |  |               |  |        |  | 4,324    |               |
|                                                                | Vanguard Institutional Target Retirement 2050 Fund    |  | Collective trust fund             |  |                  |  |               |  |        |  | 1,740    |               |
|                                                                | Vanguard Institutional Target Retirement 2055 Fund    |  | Collective trust fund             |  |                  |  |               |  |        |  | 1,298    |               |
|                                                                | Vanguard Institutional Target Retirement 2060 Fund    |  | Collective trust fund             |  |                  |  |               |  |        |  | 412      |               |
|                                                                | Total common/collective trust funds               |  |                                   |  |                  |  |               |  |        |  | 371,060  |               |
|                                                                |                                                       |  |                                   |  |                  |  |               |  |        |  |               |
|                                                                | T. Rowe Price Small Cap Stock Fund                    |  | Mutual fund                       |  |                  |  |               |  |        |  | 7,500    |               |
|                                                                |                                                       |  |                                   |  |                  |  |               |  |        |  |               |
|                                                                | Diversified Bond Fund - Core                          |  | Mutual fund                       |  |                  |  |               |  |        |  | 17,826   |               |
|                                                                | Diversified Bond Fund - High Yield                    |  | Mutual fund                       |  |                  |  |               |  |        |  | 987      |               |
|                                                                | Diversified Bond Fund - Emerging Markets              |  | Mutual fund                       |  |                  |  |               |  |        |  | 989      |               |
|                                                                | Total mutual funds                                    |  |                                   |  |                  |  |               |  |        |  | 27,303   |               |
|                                                                |                                                       |  |                                   |  |                  |  |               |  |        |  |               |
|                                                                | Total investments                                     |  |                                   |  |                  |  |               |  |        |  | 513,259  |               |
|                                                                |                                                       |  |                                   |  |                  |  |               |  |        |  |               |
| *                                                              | Notes receivable from participants                    |  | Interest Rates: 3.25% - 9.50% |  |                  |  |               |  |        |  | 2,736    |               |
|                                                                |                                                       |  | Maturity Dates: 2022- 2036    |  |                  |  |               |  |        |  |               |
|                                                                | Total                                                 |  |                                   |  |                  |  |               |  |        |  | $             | 515,995  |  |

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|               |              |   |                                                          |  |  |  |  |  |  |  |  |
|---------------|--------------|---|----------------------------------------------------------|--|--|--|--|--|--|--|--|
| Exhibit Index |
|               |              |   |                                                          |
|               | Exhibit 23.1 | - | Consent of Independent Registered Public Accounting Firm |

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|                                                           |  |  |
|-----------------------------------------------------------|--|--|
| PFIZER SAVINGS PLAN FOR EMPLOYEES RESIDENT IN PUERTO RICO |
|                                                           |
| By: /s/ Colum Lane                  |
|                                                           |
|                                                           |
| Colum Lane                                                |
| Member, Savings Plan Committee                            |