Alexandria Real Estate Equities Inc. on Thursday priced a larger secondary public offering of 4 million shares at $53.25 a share, a 6 percent discount to the stock’s Wednesday’s close.

The Pasadena real estate investment trust, which invests in health care and biotech properties, plans to use net proceeds to reduce the balance on its unsecured line of credit so that it can use that line for general corporate purposes, such developing or redeveloping properties.

The amount to be sold now is up from the 3 million first announced Wednesday. The offering is expected to close on Sept. 29.

The company said it expects to grant the underwriters – Barclays Capital, Credit Suisse and UBS Investment Bank – a thirty-day option to purchase up to 600,000 additional shares to cover any over allotments, also up from the 450,000 originally announced.

Alexandria had 39 million shares outstanding prior to the offering.

Shares closed down $3.44, or 6 percent, to $53.29 on the New York Stock Exchange. The share price also declined 6 percent Wednesday following the initial announcement of the offering.