When Harry J. Baum's employer, the Martin Marieta Aerospace Corp., recently transferred him from Denver to Bethesda, Baum sold his Colorado house -- with its 9 percent mortgage interest rate -- and bought a home in Damascus financed at 12 1/2 percent interest.

Martin Marietta is cushioning the blow, however. The company is paying a portion of Baum's new mortgage for three years to compensate him for having to buy when interest rates were soaring.

"It will be a tremendous help," Baum said. "It certainly made the move easier."

Faced with the prospect of buying a more expensive home at a time of double-digit interest rates and economic uncertainty, more and more employes here and elsewhere are balking at moving.

So, like Martin Marietta, an increasing number of companies are offering incentives to make out-of-town transfers more attractive to their workers.

Homequity Inc., a Connecticut-based national relocation company that specializes in corporate moves, estimates that a year ago it cost companies an average of $20,500 to move a family of four about 900 miles.

Today that same move costs about $30,000, an increase of 48 percent. High interest rates account for the biggest portion of that increase.

"Since September, the (real estate) industry has been revolutionized," said Theodore W. Robinson, manager of public relations for Homequity. "The industry is in a depression, while the rest of the country and other industries are in a recession."

Many companies have special mortgage programs. For example, if a General Motors employe with a $50,000 house and an 8 percent mortgage is transferred and buys a $100,000 house with a 12 percent mortgage, the company will pay the 4 percent difference -- based on the $50,000 base price -- for three years.

Pat Matteson, director of marketing for Merrill Lynch Relocation Management Inc., a subsidiary of Merrill Lynch and Co. based in White Plains, N.Y., said a corporate client's typical mortgage rate program would pay about $3,600 a year for three to five years to a worker with a $60,000 mortgage at 10 percent interest who buys a house with a $60,000 mortgage at 16 percent interest.

The payment would be considered taxable income to the employe; however, some companies find ways to absorb the cost of the tax for their workers.

Merrill Lunch also has set up a program to enable a transferred employe to buy a house at his or her new location at today's price. Make the down payment, pay a monthly carrying charge and have up to a year to arrange a mortgage, Matteson said.

An assumption of many of the programs that encourage transferred workers to move are ploys that interest rates will be lower this time next year -- a belief held by many housing experts.

Mortgage interest rates already have declined, from record highs of about 17 percent down to about 13 percent at some institutions as of last week. But many potential home buyers still are reluctant to buy now because they fear a recession, while others believe that if they wait a few more months, interest rates might decline further.

Fluctuations in the real estate market make a relocation company's job difficult.

Under a contract with a corporation, a company like Homequity offers to buy a transferred employe's home based on an appraisal of the property's value, and markets it for resale through independent brokers. Homequity earns its money by charging the company a service fee that usually is about 1 to 2 percent of the value of each home it buys, and helps workers find new homes and adjust to pulling up roots.

It now takes longer to sell homes, and houses that would have sold with little effort a year ago now require sprucing up and repairs before they can attract buyers. Potential buyers may even be cajoled into a sale when offered a two-year free supply of oil for their homes.

Homequity has been advising its clients to avoid or postpone relocations whenever possible now. For moves that must be made, workers are urged to consider renting at their new locations for a while and employers are advised to set up mortgage compensation programs.

Since movers to the Washington area find buying a home can be particularly harrowing. Not only are interest rates high, but housing prices are among the highest in the country.

When Michael J. Shaw, who has worked for the Continental Telephone Corp. for 15 years, was transferred from its Atlanta headquarters to Washington recently, he found housing prices about 30 percent higher here than in Atlanta for comparable homes. Shaw finally bought a $90,000 town house in Reston.

Kim Haines, manager of relocation services for Routh Robbins Realtors, whose clients are individuals rather than corporations, said many employes refuse to be transferred here when they see the kind of house they get for their money. "Some are saying they're just not interested in rerlocating," Haines said.