The editing process and eventual completion of the rule - which places limits on banks' trading abilities - requires the sign-off of five government agencies, and previous drafts have swelled to 300 pages. (Read More: Volcker Rule: CNBC Explains )
Due to the complexity of the rule, the challenges of agency coordination and the volume of feedback regulators received, officials are now pointing to the first quarter of 2013 as a more tenable deadline, instead of the year-end goal telegraphed previously by participants like Martin Gruenberg, acting chairman of the Federal Deposit Insurance Corp.
"Our goal is to achieve a strong and consistent rule, although the process is not as easy or simple as any of us would like," said Treasury Undersecretary Mary Miller in prepared remarks at a recent banking conference. Miller noted that regulators had received more than 18,000 comment letters on the proposed rule, but were making "steady progress" toward its implementation.
At its core, the rule aims to restrict banks from making certain speculative investments for their own gain - also known as proprietary trading. Such practices came under harsh scrutiny during the financial crisis when banks made big bets based on the direction of the economy, while advising clients otherwise. (Read More: Inside America's Economic Crisis )
The Federal Reserve, the CFTC, the SEC, the FDIC and the OCC have been toiling over the rule's exact language since Dodd-Frank was passed in July 2010, and the financial sector has been watching the process with a keen eye. One of the biggest worries relates to language around core client functions, like using derivatives to hedge against swings in interest rates for corporate clients of all sizes. (Read More: Dodd-Frank Act: CNBC Explains )
That risk will be the focus of a hearing being planned by the House Financial Services Committee for Dec. 13, where testimony is expected from treasurer-level executives that some in Congress worry could become unintended victims of the rule's expansion, according to officials with knowledge of the hearing. (Read More: 'No More Excuses' from Banks or Regulators: Analyst )
Previously, the committee had hoped to schedule the five regulators for the hearing, in order to glean information about the drafting progress and the safeguards for Main Street businesses. Due to conflicts with the December FOMC meeting schedule, officials said, the scope of the hearing was changed. (The Fed - along with the SEC - is said to spearhead the Volcker effort but declined to comment on its progress.)
While Congress does not play a direct role in the process, it has been instrumental in collecting wide-ranging commentary on Volcker and any potential fallout. Additionally, the Financial Services Committee this fall called for suggestions on "alternatives" to the Volcker Rule - which, officials note, was also to prepare for the possibility of steep changes to regulation if Pres. Obama did not win a second term.
-By CNBC's Kayla Tausche; Follow her on Twitter: @KaylaTausche