MF Global executives, including Jon Corzine, will be called before a congressional panel to answer questions about the downfall of the trading firm and the customer money that remains missing since its final days, according to people familiar with the matter. The House Financial Services Committee has tentatively set December 15 for a public hearing on MF Global.  The Committee's Oversight Unit reportedly plans to call, among others, CEO Corzine and COO Bradley Abelow - who also served as NJ Governor Corzine’s chief of staff. Top regulators also will be invited to testify - including SEC Director Robert Cook (Trading and Markets Division); and CFTC Chairman Gary Gensler, though he recused himself from the investigation because of a conflict of interest. First order of business will likely be the issue of the missing customer funds - which could range between $600mn and $1.2bn. It's uncertain whether Abelow, who's still at MF Global, and Corzine, who resigned earlier this month, will accept the invitation to testify, though they could be subpoenaed, if necessary. Concurrent Federal Investigation. The hearing would overlap with the government's intensifying investigation of MF Global's books and records.  Court-appointed trustee James Giddens and CFTC staffers lead the search for the missing money, while the FBI and federal prosecutors in New York and Chicago examine for potential criminal wrongdoing. Findings so far indicate that much of the customer funds left the firm, and can be considered gone.  Regulators suspect that MF Global used at least some of the money to meet their own financial obligations.  If that proves to be the case, there will be little chance of recovering any of the funds. Neither the firm nor Mr. Corzine have been accused of any wrongdoing.  [Dealbook 11/22/11]