| Summary of Marketable Securities |
As of April 30, 2022 and January 31, 2022, our marketable securities consisted of the following: | | | | | | | | | | | | | | | | | | | | | | | | | As of April 30, 2022 | | Amortized
Cost | | Gross
Unrealized
Gains | | Gross
Unrealized
Losses | | Estimated
Fair
Value | | | | | | | | | | (in thousands) | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commercial paper | $ | 34,881 | | | $ | — | | | $ | — | | | $ | 34,881 | | | Agency bonds | 604,439 | | | 1 | | | (10,043) | | | 594,397 | | | Corporate and other debt securities | 288,312 | | | 1 | | | (3,062) | | | 285,251 | | | U.S. government agency securities | 3,192,672 | | | 43 | | | (46,657) | | | 3,146,058 | | | Treasury bills | 258,595 | | | 1 | | | (209) | | | 258,387 | | | Marketable securities | $ | 4,378,899 | | | $ | 46 | | | $ | (59,971) | | | $ | 4,318,974 | |
| | | | | | | | | | | | | | | | | | | | | | | | | As of January 31, 2022 | | Amortized
Cost | | Gross
Unrealized
Gains | | Gross
Unrealized
Losses | | Estimated
Fair
Value | | | | | | | | | | (in thousands) | | | | | | | | | | | | | | | | | | Commercial paper | $ | 28,723 | | | $ | — | | | $ | — | | | $ | 28,723 | | | Agency bonds | 632,935 | | | 2 | | | (3,328) | | | 629,609 | | | Corporate and other debt securities | 282,124 | | | 5 | | | (1,202) | | | 280,927 | | | U.S. government agency securities | 3,046,742 | | | 28 | | | (19,261) | | | 3,027,509 | | | Treasury bills | 389,826 | | | — | | | (148) | | | 389,678 | | | Marketable securities | $ | 4,380,350 | | | $ | 35 | | | $ | (23,939) | | | $ | 4,356,446 | |
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| Summary of Contractual Maturities of Marketable Securities |
The following table presents the contractual maturities of our marketable securities as of April 30, 2022 and January 31, 2022: | | | | | | | | | | | | | As of | | April 30, 2022 | | January 31, 2022 | | | | | | (in thousands) | | Less than one year | $ | 2,624,024 | | | $ | 2,387,139 | | | Due in one to five years | 1,694,950 | | | 1,969,307 | | | Total | $ | 4,318,974 | | | $ | 4,356,446 | |
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| Summary of Strategic Investments |
Strategic investments by form and measurement category as of April 30, 2022 were as follows: | | | | | | | | | | | | | | | | | | | | | | | | | Measurement Category | | Fair Value | | Measurement Alternative | | Equity Method | | Total | | | | | | | | | | (in thousands) | | Equity securities | $ | 133,013 | | | $ | 102,150 | | | $ | 93,653 | | | $ | 328,816 | | | Debt securities | 14,344 | | | — | | | — | | | 14,344 | | | Strategic investments | $ | 147,357 | | | $ | 102,150 | | | $ | 93,653 | | | $ | 343,160 | |
Strategic investments by form and measurement category as of January 31, 2022 were as follows: | | | | | | | | | | | | | | | | | | | | | | | | | Measurement Category | | Fair Value | | Measurement Alternative | | Equity Method | | Total | | | | | | | | | | (in thousands) | | Equity securities | $ | 168,784 | | | $ | 91,399 | | | $ | 93,400 | | | $ | 353,583 | | | Debt securities | 14,231 | | | — | | | — | | | 14,231 | | | Strategic investments | $ | 183,015 | | | $ | 91,399 | | | $ | 93,400 | | | $ | 367,814 | |
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