Former treasury secretary William E. Simon appeared in a photo accompanying a story in yesterday's Style section of the wedding of Margaret Lyford Greene and Edward Harley Yeo III. Simon was incorrectly identified in the photo caption.

Who says there is no romance in banking? An unusual wedding here Saturday night was enough to send any reserve currency fluttering.

Margaret Lyford Greene, the vice president of the Federal Reserve Bank of New York responsible for U.S. government foreign exchange operations, married Edward Harley Yeo III, the former undersecretary of the Treasury for monetary affairs during the Ford administration. Yeo is now chairman of the asset and liability committee for the country's 9th largest bank, the First National Bank of Chicago.

To honor the occasion, a glittering array of financial and banking officials assembled for the double-ring ceremony at the Reformed Church.

Best man was William Simon, former secretary of the Treasury. And the ushers included Dr. Arthur Burns, the former chairman of the Federal Reserve Board of Governors; Jacques de Larouiere, current managing director of the International Monetary Fund: "Rafael Izaquierdo, adviser to the president of Mexico; Karl Otto Poehl, deputy governor of the Deutsche Bundesbank; William D. Rogers, former undersecretary of State; and A. Robert Abboud, chairman of the First Chicago Corp., which is the holding company for Yeo's bank.

The bride, the groom and many of the officials had spent the week attending the annual meetings of the World Bank and IMF in Washington, and had rushed up to New York Friday for wedding rehearsals. The wedding had been deliberately planned to follow the IMF session.

"We met professionally," the bride (who is known as Gretchen) said before the ceremony. "He was interested in what was going on in the foreign exchange markets, which was his responsibility at the Treasury, and I was on the desk at the Federal Reserve Bank of New York. But we never saw each other socially at the time."

Mrs. Yeo, 36, joined the Fed as an economist in 1967, was appointed chief of financial statistics in 1972, was named an officer later that year and currently has the day-to-day responsibilities for carrying out operations to defend the dollar.

The couple will be maintaining residences in Manhattan, Chicago and on Cape Cod.

"We'll be together weekends, and insofar as business responsibilities permit us," said Mrs. Yeo. "We're already supporting the telephone company and the airlines."

Meanwhile, some questions have been raised about whether Mrs. Yeo will be able to continue her present duties at the Fed after the marriage, because of the appearance of a conflict-of-interest since her job is one of the most sensitive in the entire Federal Reserve System, and she is privy to information that would be of interest to any large bank, including her husband's.

"In this day of women's liberation, we'll just have to wait and see what happens," said her boss, Paul Volcker, president of the Federal Reserve Bank of New York, and another guest at the wedding.

The bride is the daughter of Mr. and Mrs. Lyford N. Greene of Scarsdale. Greene retired as the director of economic analysis for the American Telephone & Telegraph Co. Yeo, 43 is the son of Mr. and Mrs. Edwin H. Yeo Jr. of Lowellville, Ohio, and Pittsburgh, Pa. His father is president of McKnight Plaza, a real estate holding company.

"This is the first wedding I've ever ushered," said a delighted Burns who put off smoking his always-present pipe until after his ushering duties were completed.

After the ceremony, a reception was held at the Westchester Country Club where many of the distinguished guests were seen buttonholing each other in corners. While it could not be learned what was specifically under discussion, speculation was that they were trying to arrange a dollar rally in celebration of the occasion.