Martin Marietta Corp., writing the last chapter in a notorious business story that is now the subject of several books, said yesterday it would pay about $280 million for the remaining 20 percent of its stock held by Allied Corp., the peacemaker in Marietta's merger battle last year with Bendix Corp.

The action will return Martin Marietta to the independence it enjoyed prior to last Aug. 25, when Bendix announced a surprise offer for the Bethesda-based aerospace conglomerate's stock.

Bendix was gobbled up by Allied in the agreement that ended the fight in late September, and Bendix Chairman William Agee, architect of the raid on Marietta, resigned earlier this year from the presidency of Allied, effective June 1.

Martin Marietta, a Bethesda-based aerospace conglomerate, announced that it had filed plans with the Securities and Exchange Commission to issue 4.65 million shares of stock, and would use the proceeds to buy a like number of its shares from Allied. The action, combined with a previously announced plan to buy back 1.8 million shares from Allied, "will eliminate Allied's holding in Martin Marietta outstanding shares," the company said. It said it expected to complete the transactions by October.

Allied, a Morristown, N.J.-based chemical and industrial giant, obtained the shares in Marietta when it stepped into the Bendix-Marietta fray, took over Bendix and got a 38 percent stake in Marietta. That percentage has been gradually reduced over the past several months as Martin Marietta has repurchased stock from Allied or issued new shares that increased the total amount of Marietta stock outstanding.

Martin Marietta officials have said over the past few months that they expected eventually to buy back Allied's holding in Marietta, although Marietta's senior vice president and chief operating officer, Laurence J. Adams, said in an interview in late April, "I don't suspect it would be the first priority for our funds right now."

Under an agreement signed by Allied and Martin Marietta officials at the time of the resolution of the Bendix-Marietta battle, Marietta was given the right to buy back the stock at any time. Allied also was prohibited by the agreement from increasing its holding and from voting or selling the stock to another company without the approval of Martin Marietta's board.