By Ilaina Jonas

NEW YORK, June 4 (Reuters) - Office landlord Boston Properties Inc (BXP.N: Quote, Profile, Research) said on Thursday it would sell more than 12 million shares, becoming the most recent real estate investment trust to tap the public equity market to raise cash.

The company, which owns top-quality office buildings in U.S. cities including New York, Boston and San Francisco, said it would sell 10.5 million shares and grant underwriters an additional 1,575,000 shares to cover overallotments.

Since the credit crisis struck and dried up sources of debt, the public real-estate companies have been able to turn to equity markets to raise cash to pay off their debt and strengthen their balance sheets.

So far this year, 45 publicly traded REITs have raised more than $14 billion from sales of new shares, with about 40 generating $11.5 billion since March. In most cases, the initial demand for shares has been so strong issuers have increased the number of shares offered.

Boston Properties said it intends to use the net proceeds from the offering for general business purposes, which may include investment opportunities and debt reduction.

Following the news of the offerings, shares of Boston Properties on Thursday fell 3.8 percent to $51.01 in after-hours activity, from their close of $53.01 on the New York Stock Exchange. (Reporting by Ilaina Jonas, editing by Matthew Lewis)