| Summary of Marketable Securities |
As of July 31, 2021 and January 31, 2021, our marketable securities consisted of the following: | | | | | | | | | | | | | | | | | | | | | | | | | As of July 31, 2021 | | Amortized Cost | | Gross Unrealized Gains | | Gross Unrealized Losses | | Estimated Fair Value | | | | | | | | | | (in thousands) | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commercial paper | $ | 33,729 | | | $ | — | | | $ | — | | | $ | 33,729 | | | Agency bonds | 491,968 | | | 82 | | | (53) | | | 491,997 | | | Corporate and other debt securities | 380,373 | | | 314 | | | (89) | | | 380,598 | | | U.S. government agency securities | 2,213,814 | | | 157 | | | (259) | | | 2,213,712 | | | Treasury bills | 53,996 | | | 1 | | | (4) | | | 53,993 | | | Marketable securities | $ | 3,173,880 | | | $ | 554 | | | $ | (405) | | | $ | 3,174,029 | |
| | | | | | | | | | | | | | | | | | | | | | | | | As of January 31, 2021 | | Amortized Cost | | Gross Unrealized Gains | | Gross Unrealized Losses | | Estimated Fair Value | | | | | | | | | | (in thousands) | | | | | | | | | | | | | | | | | | Commercial paper | $ | 26,222 | | | $ | — | | | $ | — | | | $ | 26,222 | | | Agency bonds | 461,335 | | | 79 | | | (49) | | | 461,365 | | | Corporate and other debt securities | 465,207 | | | 1,113 | | | (64) | | | 466,256 | | | U.S. government agency securities | 834,894 | | | 28 | | | (257) | | | 834,665 | | | Treasury bills | 215,902 | | | 6 | | | (6) | | | 215,902 | | | Marketable securities | $ | 2,003,560 | | | $ | 1,226 | | | $ | (376) | | | $ | 2,004,410 | |
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| Summary of Contractual Maturities of Marketable Securities |
The following table presents the contractual maturities of our marketable securities as of July 31, 2021 and January 31, 2021: | | | | | | | | | | | | | As of | | July 31, 2021 | | January 31, 2021 | | | | | | (in thousands) | | Less than one year | $ | 1,660,900 | | | $ | 1,017,048 | | | Due in one to five years | 1,513,129 | | | 987,362 | | | Total | $ | 3,174,029 | | | $ | 2,004,410 | |
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| Summary of Strategic Investments |
Strategic investments by form and measurement category as of July 31, 2021 were as follows: | | | | | | | | | | | | | | | | | | | Measurement Category | | Fair Value | | Measurement Alternative | | Total | | | | | | | | (in thousands) | | Equity securities | $ | 107,076 | | | $ | 15,288 | | | $ | 122,364 | | | Debt securities | 15,431 | | | — | | | 15,431 | | | Strategic investments | $ | 122,507 | | | $ | 15,288 | | | $ | 137,795 | |
Strategic investments by form and measurement category as of January 31, 2021 were as follows: | | | | | | | | | | | | | | | | | | | Measurement Category | | Fair Value | | Measurement Alternative | | Total | | | | | | | | (in thousands) | | Equity securities | $ | — | | | $ | 13,538 | | | $ | 13,538 | | | Debt securities | 5,130 | | | — | | | 5,130 | | | Strategic investments | $ | 5,130 | | | $ | 13,538 | | | $ | 18,668 | |
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