Posted Monday 7:30 p.m. In an aggressive change of course, Yale will increase the amount of money it spends from its endowment by nearly 40 percent next year in part to provide more financial aid to students and to launch new research on the West Campus, University President Richard Levin announced Monday.

The move comes after months of pressure from Congress and other critics who assailed Yale and other top universities for not being generous enough with spending their endowment riches, and in preparation for the University’s highly anticipated unveiling next week of a new financial-aid initiative.

Yale will spend about $1.15 billion from the endowment in the next fiscal year, an increase of 37 percent over the $843 million endowment payout this year, the University said in a statement. In addition to targeting financial aid and scientific research, the new money will help pay for expanding access to Yale’s resources through digitization of its library collections and other projects and for the possible accommodation of a larger student body following the addition of two new residential colleges.

Levin told Bloomberg News on Monday that Yale’s “historic” financial-aid reforms will be aimed at students whose families earn as much as $200,000 a year.

Yale’s endowment spending is governed by a complicated “spending rule” that takes into account inflation as well as the growth of the endowment in recent years. The rule, according to Yale officials, is designed to protect the endowment from the volatility of the investment market.

But as the University’s endowment posted double-digit returns in recent years, the spending rule prevented any commensurate increase in endowment spending. As a result, Yale’s spending from its endowment dwindled from its goal of 5.25 percent to this year’s 3.7 percent, a number Levin said was excessively low.

“While the rule [limiting endowment spending] is designed to ensure the purchasing power of the endowment over the long haul, by the same token, it’s supposed to be responsibly trading off the needs of the present with the needs of the future,” Levin said in an interview on Monday.

But because the endowment had soared in recent years without significant increases in spending, “It became increasingly clear to us … that we might be shortchanging the present generation,” Levin said.

The forthcoming financial-aid initiative — which Levin said will be commensurate to sweeping financial-aid changes aimed at upper-middle-class families that Harvard announced last month — will all but require the University to dip into its endowment, according to an analysis conducted by the News last month of University budget documents.

Levin said the University had been considering modifying its rules regarding endowment spending for several years, and the public debate on the topic in recent months further encouraged Yale to make a change.

In October, Iowa Senator Chuck Grassley, the ranking member of the Senate Finance Committee, publicly called out Yale and other schools, which he said have continued to raise tuition annually in spite of soaring endowment returns that could easily have offset any increase in student costs.

Grassley proposed that colleges with endowments exceeding $500 million be required to spend at least 5 percent of their endowments on an annual basis, essentially forcing them to freeze tuition increases or bolster financial aid.

The University’s target endowment payout has been 5.25 percent since 2004. But because the endowment has increased so sharply in recent years, this year’s endowment spending is only 3.7 percent, since the spending rule does not allow endowment spending to increase commensurate to investment returns.

Now, the formula will be modified so as to preclude spending less than 4.5 percent or more than 6 percent of the endowment annually, the Unive

Yale’s endowment, at $22.5 billion, is the second highest of any American university, trailing only Harvard’s, at $34.9 billion.