A plan by a PIMCO investment fund to take an ownership stake in a small North Carolina bank has run into a problem with U.S. bank regulators.

A group of investors led by Pacific Investment Management Co and the parent company of East Carolina Bank are now revising a recapitalization plan for the Engelhard, North Carolina-based lender, according to a statement from the bank and comments from its chief executive officer.

In the deal, the $2.3 billion PIMCO Bravo Fund - which is short for Bank Recapitalization and Value Opportunities - and five other investors had planned to commit $79.7 million to ECB Bancorp Inc . The parent of East Carolina Bank was then going to use some of that money to complete the acquisition of several branches from Virginia-based Hampton Roads Bankshares Inc .

ECB Bancorp CEO A. Dwight Utz said the investors and the bank expect to submit a revised plan to the Federal Reserve Bank of Richmond. He also said Hampton Roads Bankshares has agreed to give East Carolina Bank more time to get the necessary regulatory approval.

Utz said the original private placement of shares was voluntarily terminated because one of the investors was not able to garner approval to move the transaction forward.

Utz declined to identify the investor.

The other two large investors in the group include Philadelphia-based Patriot Financial Partners and New York-based Endicott Management. Three smaller firms also put money into the deal.

In a September filing with the Securities and Exchange Commission, ECB Bancorp said the Board of Governors of the Federal Reserve System must approve each of PIMCO Bravo Fund's and Patriot's proposed investment in the Company prior to the consummation of the private placement offering.

A spokeswoman for the Richmond Fed declined to comment. A spokesman for Newport Beach, California-based PIMCO, which oversees $1.4 trillion, did not respond to a request for comment. And calls to Patriot Financial seeking comment were not returned.

The ECB Bancorp recapitalization is one of the PIMCO Bravo fund's first major bank transactions. In the original deal, the PIMCO fund, which intends to acquire commercial and residential mortgage loans and other debt, was paying $25 million for a roughly 20 percent equity stake.

PIMCO, Patriot and Endicott, as the three largest investors in the group, were each going to get to name a director to sit on ECB Bancorp's board under the original plan.

The PIMCO Bravo fund is part of a move by PIMCO co-founder Bill Gross into other investments beyond bonds, which PIMCO and Gross are best-known. Gross' PIMCO Total Return Fund, with $250 billion in assets, is the world's largest bond fund.

Last year, PIMCO was granted full control of its various investment products by its parent company, Allianz SE - a move that gives the firm more independence to expand into new businesses.

(Reporting By Matthew Goldstein and Jennifer Ablan)