CBS Stock Buyback Is Oversubscribed : Securities: The $2-billion repurchase plan lures tenders for twice as much stock as it wanted. So it will accept shares on a prorated basis.

NEW YORK —  CBS Inc. said Wednesday that its $2-billion offer to buy back about 44% of its common stock attracted tenders of about twice as many shares as the company wanted to repurchase.

As a result, the media giant said it expects to buy a prorated share amounting to about 48.2% of the stock tendered in completing its $190-a-share repurchase. The precise figure won’t be established until Feb. 1.

In trading on the New York Stock Exchange, CBS shares tumbled $13 a share to $153.

But analysts had expected the decline in the aftermath of the stock buyback because of the poor earnings prospects for CBS and the network television business in general. CBS has said it expects to report a rare loss for the fourth quarter and lower earnings in 1991, partly because of the tough advertising market.

CBS had announced in mid-December that it would buy back up to 10.5 million of its 24 million common shares for $190 a share.

It intended to pay for the buyback by using some of the $3 billion in cash it has amassed in recent years through the sale of the company’s records, magazine and book publishing businesses.

The tender offer expired at 5 p.m. EST Tuesday, and CBS said in a statement on Wednesday that a preliminary count showed that nearly 21.8 million shares had been tendered.

It said both the Loews Corp., the company controlled by CBS Chairman Laurence A. Tisch and his family, and the estate of the late CBS founder William S. Paley had tendered all of their stock in the buyback.

Loews, CBS’ biggest single shareholder, owned 5.8 million shares and would realize about $531 million for 48.2% of its stock. Loews reportedly had bought its stake for an average of $127 a share, meaning it would realize a profit of about $176 million on the shares sold back.

After the buyback, the Loews stake would fall to about 23% from 24.9%, while the Paley estate’s holdings would drop to about 5% from 5.5%.

The Paley estate had indicated that it needed to sell some of its CBS stock to pay estate taxes. Paley died in late October.

The buyback will leave CBS with about 13.2 million shares outstanding.