Signature Bank, a New York-based full service commercial bank with a large private client business, said it had made a public offering of 3,500,000 shares of its common stock.

The bank said it will also grant to the underwriters a 30-day option to purchase up to 525,000 additional shares of common stock from the bank to cover over-allotments, if any.

Friedman, Billings, Ramsey & Co. is expected to act as lead manager in the offering. Oppenheimer & Co. and Sandler O'Neill & Partners are expected to act as co-managers on the public offering, Signature said in a statement.

Signature Bank has 21 private client offices located in the New York metropolitan area, serving privately owned businesses through dozens of private client groups.