The following table summarizes the total carrying value of the Company’s non-marketable equity securities held as of March 31, 2023 including cumulative unrealized gains and losses: | | | | | | | March 31, 2023 | | (in millions) | | Initial cost basis | $ | 754 | | | Adjustments: | | | Upward adjustments | 829 | | | Downward adjustments (including impairment) | (438) | | | Carrying amount, end of period | $ | 1,145 | |
Unrealized gains and losses included in the carrying value of the Company’s non-marketable equity securities still held as of March 31, 2023 and 2022 were as follows: | | | | | | | | | | | | | | | | | | | | | | | | | Three Months Ended March 31, | | Six Months Ended March 31, | | 2023 | | 2022 | | 2023 | | 2022 | | (in millions) | | Upward adjustments | $ | 2 | | | $ | 2 | | | $ | 19 | | | $ | 226 | | | Downward adjustments (including impairment) | $ | (89) | | | $ | (53) | | | $ | (89) | | | $ | (53) | |
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