Citi has written to the Securities and Exchange Commission urging the regulator to dismiss Nasdaq OMX's $62 million compensation offer for its "mishandling" of the Facebook IPO.
The 18 May IPO was beset by technical glitches - including a malfunction in the system's design for processing order cancellations - that left market makers unsure of whether trades went through.
Nasdaq OMX initially set aside $40 million to compensate firms' losses before upping the figure in its SEC submission to $62 million.
However, the package is still sharply contested, with UBS alone claiming to have lost $357 million and threatening legal action. According to Reuters, the Citi Automated Trading Desk is around $20 million out of pocket.
In its letter to the SEC, the bank says: "Nasdaq was grossly negligent in its handling of the Facebook IPO, and as such, Citi should be entitled to recover all of its losses attributable to Nasdaq's gross negligence, not just a very small fraction as is currently the case under the proposed SEC Submission."
The bank slams Nasdaq OMX for failing to carry out proper testing, insisting: "Market participants' losses resulted not from the type of ordinary system failures contemplated by Rule 4626 (ie, its systems' failure to correctly process acknowledged orders), but rather from a known design flaw that resulted in a similar technology issue dating back to Fall 2011".
Citi also says that the exchange operator should not be able to limit the amount of compensation it is liable for because it was acting in a regulatory capacity, arguing: "The law is clear that Nasdaq does not enjoy immunity from liability for its misdeeds where it was acting in its capacity as a profit-maximising, publicly-held corporation."