Gerspach added that "there are elements of the DTA that come about because of actual tax returns that are filed, you can see that mostly in the foreign tax credits, and we'll give you a full rundown of that when we publish the 10K in a couple of weeks, but then there is also a whole series of timing-related issues, and that mostly comes about as a result of reserve movements," according to a transcript of Tuesday's call. After reviewing the sections of the transcript dealing with the DTA, tax expert Willens said he could make little sense of Gerspach's explanation. "The only thing I could even remotely comprehend was I think he was trying to explain why the DTA was going up," Willens said. Willens has argued in the past that Citigroup should reduce the DTA through what is known as a valuation allowance. Companies are supposed to record a valuation allowance instead of a DTA when they believe there is a less than 50% chance they will be able to make use of the tax credits. If the likelihood improves, they can always convert the valuation allowance into a DTA. Willens argues regulators may eventually force Citigroup to reduce the size of its DTA on the expectation that the bank won't be profitable enough to use it before it expires. Informed of Willens' continued criticism of Citigroup's accounting, a Citigroup spokeswoman responded with an emailed statement. "As we've noted in regulatory disclosures, Citi's DTA is based on enacted tax laws and rates. Citi believes that the realization of the recognized net DTA is more likely than not based upon expectations of future taxable income in the jurisdictions in which the DTAs arise and available tax planning strategies, including asset sales, that would be implemented to prevent the carry-forward from expiring. Accounting rules would not allow for an adjustment to the DTA unless there is a change in this position and its underlying support," the statement read. Investors and analysts who follow Citigroup are increasingly sympathetic to this view. CLSA analyst Mike Mayo, for example, began recommending Citigroup in October for the first time in years following the board's ouster of CEO Vikram Pandit. While he had been an outspoken critic of Citigroup's decision not to take a valuation allowance, he called that "water under the bridge" in a January conference call where he and Willens discussed the DTA with investors.