Part of the reason revenues remain high is that donors are paying off pledges left over from the campaign, Feagin said, but she adds that there's more to the dynamic.

"During a campaign, you get people engaged in the institution. As long as you don't quit paying attention to them, then they'll keep giving," Feagin said.

Rudenstine says when people give during a campaign, they realize they can achieve a new financial commitment to the institution and afterwards they usually continue it.

"The first gulp isn't as hard as the second [one]," says Jerome T. Murphy, dean of the graduate school of education.

Most of the money raised after a campaign does not, however, come from large, capital gifts like those common during a campaign. Rudenstine says that it's difficult to keep finding new donors who can give large gifts.

The other reason fund raisers have begun to see this plateau affect is that it's the culture of campaigning today.

"If costs go up every year we don't have that many options. We can't simply raise fees, and since the endowment has to be prudently spent for a long time, universities have used annual fundraising," Rudenstine said.

When this campaign is over, Rudenstine said he will begin University-wide academic planning again--the forerunner to a campaign, though Harvard has no specific plans about when it will launch another one.

"When a campaign is over, you take a long weekend and then you get started fundraising again," Murphy said.

In this environment, fundraisers say campaigns are used to solicit large gifts and usually to double the annual gift revenue. And when an institution isn't in a campaign, they are just fundraising.

"Now we're doing the same thing day in and day out, and during [a] certain part of that, we will give our fundraising a special flavor called a campaign," Holcombe said.