Over the past five years, the average capital gain on the sale of an existing home, after deducting transaction costs, was more than $25,000, which has helped fuel major increases in consumer spending, Federal Reserve Chairman Alan Greenspan said yesterday.

In a speech telecast to a group of community bankers, Greenspan said homeowners had also tapped the equity in their houses and condominiums through home-equity loans and mortgage refinancings in which the new mortgage exceeded the old. Collectively, these two channels had provided owners with as much spendable cash as sales, according to research by Fed economists, he said.

"Although . . . the appreciation of stock prices has been vastly greater than that of home prices, most estimates suggest that stock market gains are consumed only gradually, with the level of consumer outlays lifted permanently by around 3 percent to 4 percent of the wealth generated by the stock market gain," he said.

"The permanent increase in spending out of housing wealth is somewhat higher, perhaps in the neighborhood of 5 percent, and is financed in a different manner," he continued. "The major reason for these significant differences in spending out of household wealth is doubtless that, while home prices do on occasion decline, large declines are rare."

That means increases in home values are "perceived to be largely permanent," in contrast with the "volatile and often ephemeral gains in stock market wealth," Greenspan said, adding that "most stock market wealth effects are associated with the highest income groups" where extra money is less likely to be spent, compared with "somewhat lower income groups where the preponderance of housing capital gains are realized."

Nevertheless, the enormous increase in stock prices has been responsible for most of the boost to consumer spending from gains in household wealth, though the two influences are hard to untangle, he said.

"The evidence suggests that, in recent years, about a sixth of the so-called wealth effect . . . stems from equity extracted from the stock of existing homes," Greenspan said.

About 40 percent of the growth in home mortgage debt during the past five years has involved this extraction of equity, most commonly through the routine process of home buyers taking on a larger mortgage than that held by a home's previous owners, he said.