The principal components of deferred tax assets and liabilities are as follows:
The valuation allowance provided against our deferred tax assets as of March 29, 2019, increased primarily due to a corresponding increase in unrealized capital losses from equity investments, certain acquired tax loss and tax credits carryforwards, and California research and development credits. Based on our current operations, these attributes are not expected to be realized, and a valuation allowance has been recorded to offset them.
As of March 29, 2019, we have U.S. federal net operating losses attributable to various acquired companies of approximately $147 million, which, if not used, will expire between fiscal 2020 and 2037. We have U.S. federal research and development credits of approximately $11 million. The research and development credits, if not used, will expire between fiscal 2020 and 2036. $89 million of the net operating loss carryforwards and $11 million of the U.S. federal research and development tax credits are subject to limitations which currently prevent their use, and therefore these attributes are not expected to be realized. The remaining net operating loss carryforwards and U.S. federal research and development tax credits are subject to an annual limitation under U.S. federal tax regulations but are expected to be fully realized. We have $3 million of foreign tax credits which, if not used, will expire beginning in fiscal 2028. Furthermore, we have U.S. state net operating loss and credit carryforwards attributable to various acquired companies of approximately $68 million and $51 million, respectively. If not used, our U.S. state net operating losses will expire between fiscal 2020 and 2037, and the majority of our U.S. state credit carryforwards can be carried forward indefinitely. In addition, we have foreign net operating loss carryforwards attributable to various foreign companies of approximately $118 million, $24 million of which relate to Japan, and will expire beginning in fiscal 2028, and the rest of which, under current applicable foreign tax law, can be carried forward indefinitely.
Table:
 | As of | 
(In millions) | March 29, 2019 | March 30, 2018
Deferred tax assets: |  | 
Tax credit carryforwards | $54 | $30
Net operating loss carryforwards of acquired companies | 51 | 32
Other accruals and reserves not currently tax deductible | 64 | 66
Deferred revenue | 54 | 94
Intangible assets | 384 | —
Loss on investments not currently tax deductible | 35 | 9
Stock-based compensation | 87 | 141
Other | 25 | 18
Gross deferred tax assets | 754 | 390
Valuation allowance | (105) | (19)
Deferred tax assets, net of valuation allowance | $649 | $371
Deferred tax liabilities: |  | 
Property and equipment | $(17) | $(5)
Goodwill | (13) | (20)
Intangible assets | — | (459)
Unremitted earnings of foreign subsidiaries | (316) | (396)
Prepaids and deferred expenses | (43) | (23)
Discount on convertible debt | (7) | (14)
Deferred tax liabilities | (396) | (917)
Net deferred tax assets (liabilities) | $253 | $(546)


Question: What is the reason for the increase in valuation allowance provided against deferred tax assets as of March 29, 2019?
Answer: due to a corresponding increase in unrealized capital losses from equity investments, certain acquired tax loss and tax credits carryforwards, and California research and development credits