What was going on when I was born?

The Congressional tax-writing committees will begin considering Wednesday a bill that would double the $450 million in tax refunds from the Treasury now available to a company with a healthy $1.3 billion of capital and surplus. The corporation that would benefit from the bill is the Federal National Mortgage Association, a Government-sponsored company with 30,000 stockholders that is listed on the New York Stock Exchange. A former Federal agency, it buys bundles of residential mortgages from lending institutions and in that way replenishes their cash so that they can make more loans. The Treasury will support the new bill at the hearings this week, despite strong opposition from its tax staff, according to Treasury officials.

The Shell Oil Company was the high bidder yesterday - offering millions more than any other oil company - as the Government, for the first time, offered leases to drill for oil in deep-water areas at the outer edge of the continental shelf. Confident of its success in deep-water drilling, which requires highly advanced technology, Shell bid $320.7 million on 54 of the 253 tracts off the mid-Atlantic coast put up for leasing by the Interior Department. Shell was the high bidder on 41 of those tracts, for a total of $306.6 million. Shell's bids accounted for more than half of the $576.8 million in total bids submitted for the tracts. The Exxon Corporation was next with bids totaling less than $100 million.

A House-Senate conference committee, after more than a month of haggling, agreed today on a new farm bill that would cost taxpayers at least $11 billion in the next four years, mostly for commodity loan and subsidy programs. In addition, consumer prices for milk and peanuts would go up next fall. The compromise the conferees accepted, with angry dissent from Democrats, was a qualified victory for President Reagan in his effort to slow Government spending on nonmilitary items. But it appeared headed for trouble in the House of Representatives, since it includes sugar and peanut clauses that the House voted down in late October.

3 HIJACKED VENEZUELAN PLANES LAND IN CUBA (By The Associated Press) - Three airliners seized by Latin American gunmen over Venezuela Monday landed in Cuba yesterday with more than 100 hostages aboard. The gunmen were immediately taken into custody, the Havana radio reported. The hijacking ended with a flight from Panama, one of several stops, and the broadcast said the planes had arrived in Havana with 11 gunmen, 89 passengers and 19 crew members aboard. Passengers and crews are expected to return home today, the Venezuelan Minister of Information, Enrique Perez Olivares, said in Caracas.

Mayor Koch denounced the striking private sanitationmen's union and the trash-collecting companies yesterday as ''irresponsible'' for their failure to resume efforts to end the walkout, which is now in its second week. Talks in the dispute between the companies and Local 813 of the International Brotherhood of Teamsters broke down Monday with no progress reported and no further meetings set. One of the carting companies' major concerns is how large a rate increase the city will allow as compensation for any wage increases won by the union. In an effort to remove that roadblock, the Mayor said in a statement, ''We are prepared to hold a rate hearing as soon as the strike is settled to pass along the costs of the labor settlement to the customers of the private carting firms, as has been done in the past.''

After a nearly four-hour meeting, the four-member Federal Trade Commission decided unanimously yesterday to sue the Mobil Corporation on antitrust grounds if it proceeds with its $6.5 billion takeover bid for the Marathon Oil Company. The F.T.C., however, said it might still permit Mobil to go ahead with its acquisition plans if it can find ''an adequate substitute'' to take over Marathon's transportation, storage and marketing operations in the Middle West, the principal reason for the antitrust objection. Herbert Schmertz, Mobil's vice president for public affairs, said that Mobil would have to study the F.T.C.'s decision before commenting on it. Earlier in the day, the United States Steel Corporation, which has cleared legal hurdles with its competing $6.3 billion bid for Marathon, said that its offer to pay stockholders $125 a share for a 51 percent controlling interest in Marathon Oil had attracted 54 million shares, or 90 percent of the company's 60 million shares outstanding. Barring a new offer by Mobil, U.S. Steel would be free to buy the 30 million shares it sought after midnight next Monday. Mobil announced on Monday, in a joint statement with the Amerada Hess Corporation, that if it was successful in taking over Marathon, Hess would purchase all of Marathon's marketing operations, thus leaving Mobil principally with Marathon's oil and gas reserves - its main reason for trying to acquire Marathon.

The way was cleared today for new candidates to enter the race for Secretary General when Salim A. Salim of Tanzania withdrew his name from further balloting. Mr. Salim, opposed by the United States on 16 rounds of voting in the Security Council, followed the lead taken by Kurt Waldheim last week. Mr. Waldheim, who is seeking an unprecedented third term as Secretary General, was vetoed 16 times by China and took his name off the ballot. Term Expires Dec. 31 Both men have indicated that they are still available if the Council remains deadlocked. But most of the Council's 15 members now believe that there will be a new Secretary General when Mr. Waldheim's term runs out on Dec. 31.

Many former Green Berets, men specially trained by the Army to be masters of the lethal arts, sell their skills to unfriendly governments and repressive regimes, according to Federal law enforcement officials and former Green Berets. These operations, concentrated in Africa, the Middle East and South America, are said by these sources to have involved dozens of the thousands of former Army Special Forces veterans, better known as Green Berets. These sources said that in many cases men were recruited by fellow veterans who contended that their missions had been sanctioned by the Central Intelligence Agency. In most cases, such contentions were apparently false, but former Green Berets, accustomed to handling sensitive and often unconventional covert tasks for the C.I.A. while on active duty, assumed that the jobs had been approved by the Government. The activities of former Green Berets have recently been a subject of increased Federal scrutiny because of disclosures that more than a dozen Special Forces veterans worked in Libya training terrorists in an operation organized by Edwin P. Wilson, a former C.I.A. agent. Mr. Wilson has been indicted on charges of illegally shipping explosives to Libya for use in training terrorists and is believed to be living there.

Deputy Secretary of State William P. Clark Jr. has said that the American people support the reunification of Ireland, inspiring private expressions of annoyance today from British officials. Those in Northern Ireland who want to remain linked with Britain have denounced what they see as an attempt by the United States to interfere in their affairs. And Prime Minister Margaret Thatcher, pressed for an explanation this afternoon in Parliament, pointedly reminded the United States that the future of the province was an exclusively British concern. The British Government is understood to be seeking an explanation from Washington of whether Mr. Clark's comment, made during an interview broadcast on Dublin television Monday night, represented a change in the frequently expressed United States Government policy of noninterference in the Irish struggle.

After listening to President Reagan's economic advisers discuss the worsened outlook for the Federal budget, Herbert Stein couldn't resist. Mr. Reagan, he quipped, ''seems to be the only member of this Administration who believes that deficits are inflationary.'' Mr. Stein, who was President Nixon's chief economist, delivered that jab today before all three members of Mr. Reagan's Council of Economic Advisers and 100 other economists at a symposium on inflation sponsored by the American Enterprise Institute, part of its fifth annual public policy week. The discussion, scheduled for weeks, was enlivened by Monday's disclosure that Administration analysts believe the current 1982 fiscal year budget deficit could climb to a record $109 billion. Estimates that have been given to Mr. Reagan also showed that, without more budget cuts or tax rises, the deficit could go to $152 billion in 1983 and $162 billion in 1984.

''I'll be 62. I've seen the elephant, heard the owl and flown with the screeching eagle.

The Commodities column in Business Day Monday misnamed the author of a report on oats. He was Christopher Stewart.