12.	Income Taxes

The provision for income taxes is determined using an estimated annual effective tax rate. The effective tax rate may be subject to fluctuations during the year as new information is obtained, which may affect the assumptions used to estimate the annual effective tax rate, including factors such as valuation allowances against deferred tax assets, the recognition or de-recognition of tax benefits related to uncertain tax positions, if any, and changes in or the interpretation of tax laws in jurisdictions where BioTime conducts business.

A valuation allowance is provided when it is more likely than not that some portion of the deferred tax assets will not be realized. BioTime established a full valuation allowance as of June 30, 2016 and December 31, 2015 due to the uncertainty of realizing future tax benefits from its net operating loss carryforwards and other deferred tax assets.

Although the Deconsolidation was not a taxable transaction to BioTime, the $49.0 million gain on the Deconsolidation of Asterias recorded by BioTime generated a deferred tax liability on the equity method investment in Asterias carried at fair value that was fully offset by BioTime’s net operating losses. Accordingly, BioTime did not record any provision or benefit for income taxes for the three and six months ended June 30, 2016. An income tax benefit of approximately $2.4 million was recorded for the six months ended June 30, 2015, of which approximately $2.6 million was related to federal taxes offset by $154,000 related to state taxes. The income tax benefit recorded for the six months ended June 30, 2015 was primarily related to the deferred tax liabilities BioTime had recorded for its acquisition of certain intellectual property.