The Washington Post Co. yesterday commenced its previously announced tender offer for 1.1 million shares, or 9 percent, of its own outstanding Class B common shares at $112 a share.

Post Co. stock closed up 3/4 yesterday at 109 1/4. At the start of the year, Post Co. stock was trading at 80 1/4.

The company said it may purchase an additional 450,000 shares if they are offered, which would bring the total number of Class B shares purchased by the company to 1.55 million, or 13 percent of the total Class B common stock currently outstanding.

The offer will expire at midnight EST on April 12 unless extended.

Stockholders who offer their shares may change their decision until midnight eastern time on April 8.

If the offer is oversubscribed, the company will buy on a prorated basis some portion of those shares tendered by midnight EST on April 8.

All shares tendered by any stockholder who beneficially owned fewer than 100 shares of Class B common stock on March 15 will be purchased by the company without proration.

The company's second-quarter dividend of 24 cents a share, payable on May 10 to stockholders of record on April 1, will be paid on all shares purchased under the offer.