Boehner, a chief negotiator in House-Senate talks on the massive bill begun last March, said the goal was to send the bill to the president for his signature as early as next week.
"We don't have an agreement yet, but we are very close," Boehner, R-Ohio, said at a news conference.
On Wednesday, after the latest of almost daily meetings on the bill in recent weeks, Senate Health, Education, Labor and Pensions Committee Chairman Michael Enzi, R-Wyo., said he thought that "everything's resolved, pending getting the exact wording."
Aides involved in the talks were more cautious, saying there still were a number of outstanding issues, including the extent of special relief that the Senate wants to give financially struggling airlines and efforts to attach various tax breaks to the bill.
Boehner stressed that the final product will strengthen the current system, under which employer-based defined benefit pension plans are underfunded by an estimated $450 billion and the Pension Benefit Guaranty Corp., the federal agency that insures these plans, is running a $22.8 billion deficit.
The difficulty is how to force companies with underfunded plans to meet their obligations to their workers without driving them to eliminate their plans, shifting the financial burden to the PBGC and, if the situation deteriorates, to taxpayers.
"We have to walk a very fine line if we are going to meet all those goals," Boehner said.
According to documents supplied by GOP aides, the final bill is expected to require all plans to be 100 percent funded in seven years. Under current law, 90 percent funding is regarded as full funding.
A new interest rate is adopted as the means to more accurately measure pension liabilities, and plans that are funded below 80 percent are barred from using cash balances, past contributions to the plans that may have overstated value because of stock market losses.
The bill is also expected to give people with 401(k) and IRA investments greater access to investment advice, a controversial issue because of concerns that some Wall Street companies offering advice might have conflict-of-interest problems.
The legislation encourages savings by including automatic enrollment for 401(k) programs.
It would also restrict the practices of companies giving deferred-compensation payouts to executives of financially troubled companies with at-risk pension plans.
Lynn Dudley, vice president of the American Benefits Council, which represents companies with pension plans, said she still hoped changes would be made in one of the central facets of the legislation, determining the formula for what plans are "at risk" and must increase contributions until they are fully funded.
The concern, she said, is that the proposed formula might capture some plans that are essentially healthy, forcing them to freeze benefits or opt out of their defined-benefit plans. "You don't want to push companies out, particularly companies with a lot of employees close to retirement," she said.
The agreement was expected to reinstate temporarily some popular tax breaks, including a corporate research and development credit and a deduction for state and local sales taxes. Lawmakers also planned to use the bill to keep some of the president's temporary tax incentives for retirement savings, first passed in 2001.
The chairman of the Senate Finance Committee, Sen. Charles Grassley, R-Iowa, said negotiators were under pressure from GOP leaders to fold in a cut in estate taxes.
"I think it's a gamble to put it in," Grassley said.
A senior GOP leadership aide, speaking on condition of anonymity while negotiations continued, said Senate Majority Leader Bill Frist, R-Tenn., wants an estate tax reduction exempting the first $5 million of an individual's estate and $10 million of a couple's.