(FORTUNE Magazine) – AT&T, Berkshire Hathaway, Honeywell, J.P. Morgan, Pfizer, Xerox, and some 70 other corporations have invested $263 million in low-income housing projects since 1987, creating 8,000 homes. In return, the companies have received tax breaks via the Low Income Housing Tax Credit, the federal government's last major support for new low-income housing not devoted exclusively to the elderly or handicapped. For example, an investment of $1 million to turn an abandoned building into apartments yields up to $1.2 million in tax benefits spread over ten years. The investment money enables local sponsors to charge lower rents because they don't have to borrow so much to build the homes and hence have less interest to pay. But the 1986 program is under the budgetary gun. Dan Rostenkowski (D- Illinois) is unwilling to use his position as chairman of the House Ways and Means Committee to guarantee another in the series of one-year extensions the credit has received. It's not that Rosty dislikes the credit: He's looking for someone else to come up with the tax dollars needed to support any of the dozen so-called extenders that are tacked on to the federal budget. Among the buildings converted to new housing under the program: Providence Place, a former parish house and convent in Indianapolis. Sixteen people live there, including Blanche, 53, and Kenneth Evans, 65, a retired truck mechanic. The couple moved in in 1988 and, says she, ''we'll be here till they put us out.'' - R.T.