An "unexpected" regulatory delay has forced M&T Bank in Buffalo, N.Y., and Hudson City Bancorp in Paramus, N.J., to delay their merger for the fourth time.

The companies announced in separate press releases Monday that the Federal Reserve Board will not act on M&T's merger application before the latest April 30 termination deadline. This time, however, the banks did not automatically extend the deadline after Hudson City's board asked for time to consider its options.

Hudson City said in its release that its board "is considering its response … and will attempt to reach a determination as soon as possible."

"We continue to believe the strategic and economic fundamentals of the merger of Hudson City and M&T are attractive to Hudson City's shareholders, customers and the communities we serve," Denis Salamone, Hudson City's chairman and chief executive, said in his company's release. "However, given the unexpected notice of delay over a holiday weekend, the board … needs more time to understand the nature and timing of the delay and its potential impact on the transaction before the board can determine its course of action."

The delay comes less than two weeks after the companies began making final preparations, including mailing ballots to shareholders seeking their approval and announcing a trading blackout of Hudson City securities. The election process has since been suspended.

The banks have until April 30 to set a new deadline for the merger.

The deal between $97 billion-asset M&T and $37 billion-asset Hudson City — announced in August 2012 — was most recently postponed in December. Regulatory concerns surrounding M&T's compliance with the Bank Secrecy Act have impeded the deal's approval.

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