As controversy continues to swirl over his bank’s accounting practices, Vikram Pandit, the normally reticent CEO of Citigroup (NYSE:C), will be hosting a lunch today with major investors of the big bank, FOX Business Network has learned.

Pandit has taken heat for his low profile as Citi’s stock hovers below $5 a share, but this afternoon, he and Citigroup CFO John Gerspach are meeting with about two dozen “institutional clients” of research firm Sanford C. Bernstein for a lunch at the bank’s headquarters in Manhattan. The meeting was set up by Bernstein bank analyst John McDonald.

A spokesman for Citi described the meeting as “private and routine,” and one that was previously scheduled. It comes, however, as the bank has been engaged in an increasingly nasty war with CSLA analyst Mike Mayo, who has issued reports questioning the bank's accounting for tax credits known as “deferred tax assets,” or DTAs.

Since the financial crisis began in 2007, Citigroup has lost tens of billions of dollars and needed a massive government bailout to survive. On paper at least, the bank is now marginally profitable. However, Mayo believes Citi has improperly inflated the value of its DTAs by as much as $10 billion, which, if Mayo is right, would produce massive losses for the bank and eat into its capital levels.

Citi believes its accounting for DTAs is accurate, and has barred Mayo from speaking with senior executives including Pandit and its CFO for nearly two years. Mayo’s criticism of the bank has gone beyond its accounting; late last week, he issued a note ranking banking sector CEOs according to stock performance. Pandit was listed in last place even as Citi recently alerted Mayo that it will schedule a meeting between he and bank executives sometime this month. (The bank won’t say if Mayo will be meeting either Pandit or Gerspach, as is usually the case during such events.)

Pandit has received criticism from investors and analysts for taking an unusually low profile for the CEO of one of the world’s largest banks. He has shunned interviews with most media outlets and rarely speaks in public. However, with the exception of Mayo, he has sat down with investors and analysts in private, as he is scheduled to do today.

Both Pandit and Gerspach are expected to be asked many of the same questions Mayo has posed about the firm’s accounting for DTAs. So far, Wall Street analysts are somewhat split over the firm’s accounting; some like Richard Bove are supporting the bank’s treatment of its DTAs.(Bove, however, has been critical of Citigroup’s decision to blackball Mayo for nearly two years).

But others, like former Securities and Exchange Commission accounting chief Lynn Turner, are questioning the bank’s DTA accounting, saying that a write-down of losses may be in order.

As first reported by FOX Business, the SEC has inquired at least twice about Citigroup’s accounting for DTAs over the past 18 months; it’s unclear if the SEC has broadened its inquiry amid the latest controversy.

A Citi spokesman says the bank has no knowledge of whether the SEC has expanded its examination of the firm’s DTA accounting.