Financial institutions that see themselves as losers in bond insurer MBIA Inc.'s (MBI) split into two companies met with the insurer's regulator Thursday to ask for a redo.

According to people familiar with the matter, the meeting held in the office of New York State Insurance Superintendent Eric Dinallo didn't result in a resolution but that talks will continue. MBIA's chief executive didn't attend.

A spokesman for Dinallo called the meeting "productive."

The issue is Dinallo's approval last month of MBIA's plan to separate its U.S. municipal-bond insurance business from its commitments to insure mortgage-backed bonds and other structured securities. MBIA transferred around $5 billion in capital from its main insurance company to capitalize the new municipal-only insurer. That leaves less capital available to pay claims on structured finance transactions, which has created a growing backlash.

Barclays Plc (BCS), JPMorgan Chase (JPM), UBS AG (UBS), Bank of America Corp. (BAC) and Merrill Lynch, which was acquired by Bank of America in January, are all believed to be part of the 15 that attended. A spokesman for UBS declined to comment. Spokespeople for the other banks were unable to immediately confirm whether their companies were involved in the talks.

Jay Brown, MBIA's chief executive, has pushed the company's counterparties to negotiate commutations or cancellations of credit default swaps that the insurer wrote on securities the banks issued.

"In almost all cases, these are the exact same large financial institutions that have already received tens of billions in government money for these exact same losses," Brown said during the company's fourth-quarter earnings conference call last month.

MBIA was able to commute four contracts during the fourth quarter. During MBIA's earnings call earlier this month, the company's chief financial officer said MBIA didn't inform its derivatives counterparties during fourth-quarter negotiations of its plans to restructure.

Adding to the pressure against the split is a lawyer representing a group of bond owners that filed a class action lawsuit in New York federal court Wednesday that seeks to reverse the restructuring. A lead attorney for the suit said he is trying to persuade derivatives counterparties to join the suit. An MBIA spokesman said the company intends to defend itself vigorously against the suit. He added that MBIA's restructuring was approved by state regulators "after a thorough examination, including an assessment ... of its ability to meet its obligations to all policyholders."

MBIA wouldn't comment on Thursday's meeting.

MBIA undertook restructuring in mid-February as part of an attempt to restart its business of selling financial guarantees on bonds issued by cities, water authorities and other public-finance entities. Its main unit was left with fewer claims-paying resources for its troubled mortgage exposures, and was downgraded by several credit-ratings firms.

Shares of MBIA traded up 4.3% recently, while shares of rival Ambac Financial Group (ABK) were up 8.3%.

Ambac also announced a plan to launch a new municipal-only insurer, called Everspan, which will operate as a subsidiary of its main insurance business, rather than the separate structure of MBIA's new insurer.

-By Lavonne Kuykendall, Dow Jones Newswires; 312-750-4141; lavonne.kuykendall@dowjones.com

(Matthias Rieker contributed to this report.)