Suppose the top management at your company decided to trim the payroll by up to 10 percent to become more efficient. And then it announced that while it was figuring out who should be fired, all jobs would be declared ''open,'' and that those who keep their jobs would be ''selected'' back into employment.

That is precisely what has been going on at the World Bank for the past two months, with the predictable result that morale is shot and work at a standstill. It is an open question whether the traumatized agency can regain enough spirit to do the important work it is supposed to do.

Moeen Qureshi, the new senior vice president for operations, promised in an interview that 90 to 95 percent of the staff will know where they stand by mid-July, and that a revitalized bank will get rolling in high gear, with actual lending topping the 1986 volume.

The trouble began last year when Barber Conable, the new president of the World Bank, was confronted with the fact that its five leading member governments -- the United States, England, West Germany, Japan and France -- had refused to sign the bank's budget. He decided that trimming the fat out of a bloated bureaucracy would be his first priority.

But even some Conable supporters acknowledge that, with hindsight, there had to be a better plan. ''The way we did it,'' says a high staffer, ''everybody was technically out of a job, and was hanging around to see if he or she was going to be retained and if so what the job would be. That caused predictable anxiety, tension and anger.''

The problem is exacerbated by the fact that 75 percent of the bank staff are foreigners, here on restricted visas that make them ineligible for the American job market. Most had come here, as the West German publication Die Welt said, ''thinking they had found a comfortable job for life with the World Bank. Not in this bank, they hadn't.'' Getting fired, in effect, means packing up and going back home.

From Conable's perspective, the refusal of the major powers to sign his predecessor's last budget was a warning that the bank's administrative costs were too high. He concluded that his own self-assignment to push the bank into a lead role in dealing with Third World problems couldn't be managed until he had streamlined the organization.

Conable's right-hand man, counselor and former Republican representative William Stanton, says there was no time to wait: ''Barber bit the bullet. I don't know of any organization that's ever done anything this big -- voluntarily -- to make itself more efficient and to bring it in line with its future responsibilities.''

The top managers decided that there were hundreds of employees whose skills didn't match the bank's needs any longer. Moreover, they knew the bank needs to hire some experts with different skills -- environmentalists, for example, given one of the bank's new preoccupations.

So, Conable has reshuffled, regrouped and abandoned some operations he feels are no longer justified. At the moment, 76 employees have been fired, out of 390 to be separated by 1988. The total could go to 600. Those to be given the pink slip will get generous separation packages -- cushy enough that the U.S. Treasury protested the largess.

Almost all observers agree that the bank has long needed a shakeup. But whatever the good intentions of top management, the result, at least in the short term, has been near bedlam. Some top-notch personnel who don't fit the new structure have quit. Qureshi admits that only 70 percent of appraisals for loans have been completed for this year, against a 90 percent figure that would have been normal.

Disgruntled staff members mounted a bitter internal campaign against Conable, calling for his resignation. Anonymous critiques circulated among the staff, some suggesting that cronyism, nepotism and racism had dominated the reorganization process and allocation of the best jobs.

Conable's aides say he knew all along that a reorganization that proposed to strip away deadwood and promote younger, more promising people over the heads of their seniors would cause temporary morale problems. ''But it was necessary,'' says one. ''There are no shortcuts to making the bank more efficient and more responsive to the needs of our customers, the governments of the Third World.''

Reorganization of the bank goes beyond the cut in staff. Responding to complaints by the United State and other governments, the bank will decentralize some operations, cut back on a lax travel policy, reduce the size of missions, eliminate duplicated functions and unify responsibilities for programs and projects in an effort to make sure that the right and left hands know what they're doing.

''Can everybody get charged up again?'' asks one doubting staffer not yet sure of his own status, but inclined to think the reorganization was necessary. ''I hope it won't affect the future, but I'm not sure. It puts the onus on the top management of the bank to win back the faith of the staff.''