NEW YORK ( TheStreet) -- FirstMerit Corp. ( FMER) shares sank as the bank holding company became the latest to announce plans for a public offering of common stock. FirstMerit said Sunday that is has commenced a $315 million public offering of common stock. FirstMerit intends to grant the underwriters a 30-day option to purchase up to an additional 15% of the number of shares sold in the offering to cover overallotments, if any. On Friday, FirstMerit Bank, NA, which is held by FirstMerit, bought Midwest Bank & Trust, which was the main subsidiary of Midwest Banc Holdings ( MBHI) and the largest of four community banks to be shuttered by regulators Friday. FirstMerit shares were lately down $1.07, or 5%, to $20.17. Volume topped 617,000 shares, which was below the 50-day average daily share volume of 1.01 million. Elsewhere, several companies filed mixed securities shelf offerings. BioSante Pharmaceuticals ( BPAX) shares fell 3.9% to $2.21 as the company filed late Friday for a $75 million mixed securities shelf offering. BioSante said it will use net proceeds from any offering for general corporate purposes, including working capital, to finance the Phase III clinical studies for LibiGel, capital expenditures and the repayment, repurchase or redemption of outstanding indebtedness. Streamline Health ( STRM) slid by 1.1% to $1.80 as the health-care information technology company filed late Friday for a $20 million mixed securities shelf offering. Net proceeds from the sale of the securities will be used for general corporate purposes, Streamline said. Chubb ( CB) shares traded higher after the insurance company filed late Friday for mixed securities shelf offering of an indeterminate amount. Net proceeds from the sale of the securities will be used for general corporate purposes, Chubb said. Shares of Chubb were up 0.9% to $51.80. Hutchinson ( HTCH) shares also rose Monday after the technology solutions company filed late Friday a $250 million mixed securities shelf offering. Hutchinson said net proceeds will be used to meet working capital requirements, fund capital expenditures, and refinance debt. Hutchinson shares were up 1.1% to $5.64. -- Written by Robert Holmes in Boston. Follow Robert Holmes on Twitter and become a fan of TheStreet.com on Facebook.