One month after a $250 million gift jump-started the development of Yale’s two new residential colleges, the University is working to close the gap to its $500 million fundraising goal.

Although University Vice President for Development Joan O’Neill declined to say precisely how much the University has left to raise, she said less than $75 million separate the Development Office from its target. O’Neill added that despite the lack of a hard-set deadline for the completion of fundraising, she hopes to collect all of the necessary funds by the end of Yale’s fiscal year in June 2014.

Both O’Neill and University President Peter Salovey said the recent gift — donated by mutual fund billionaire Charles Johnson ’54 — has brought new energy to the project, which began in 2008 but floundered during the financial crisis and ensuing economic slowdown. The sudden $250 million boost toward the University’s goal has shown potential donors “a light at the end of the tunnel” for the new residential colleges, Salovey said.

“The announcement gave people a clear sense that we have a very targeted goal to raise in order to move forward on the colleges,” O’Neill said. “That’s very motivational, it gives [alumni] a clear sense of how they can make a difference.”

Still, Yale does not plan to break ground on the colleges until February 2015, according to a University-wide email from Provost Benjamin Polak sent earlier this month. The two new colleges are estimated to be completed in 2017.

The announcement of the Johnson gift informed the Yale community that there was still $80 million to raise at the end of September. In the hours following the announcement, Salovey received a call from a personal friend of Johnson’s pledging a further $5 million to the residential colleges, leaving $75 million left to raise.

Although she did not provide the specifics of the remaining sum, O’Neill said she hopes to have more news soon. Other staff members at the University’s Development Office declined to comment on the status of fundraising for the colleges.

Though many alumni were on campus earlier this month for Salovey’s inauguration, O’Neill said the weekend was not a fundraising event and that she had not expected donors to commit to making major gifts. Still, O’Neill said that expanded access to Yale, in particular through the new colleges — which will be entirely funded by donations — was a theme of the inauguration.

But in the following weeks, Salovey has been focused on fundraising, adding that he has spent “several days on the road.” The new residential colleges have likely been a primary topic of discussion, O’Neill said.

At the same time, the University continues to advertise opportunities to name physical spaces in the new colleges, which it refers to as the “North College” and the “South College,” on the website of the Development Office.

Among the spaces listed are the North College West Tower, which a donor can name for $100 million, the South College Tower, for $50 million and a fitness center for $1 million. O’Neill said some of these spaces have already been tentatively reserved for naming by major donors to the colleges.

“We have some that are on hold while the donors are thinking about what they may want to do,” O’Neill said. “Sometimes they’ll decide that they want to name it for themselves, sometimes they’ll want to name it for a [relative or someone they admire.]”

O’Neill declined to say which spaces have been reserved. She also declined to say whether the University has made any progress in naming the colleges.

Beyond physical spaces, development efforts for the colleges have focused on securing funding to support the additional 800 students who will live in the new colleges.

“The extension of [residential colleges] 13 and 14 is more than just bricks and mortar,” Yale College Dean Mary Miller said. “Perhaps the single most important consideration for me is making sure the funding is in place to underpin the expansion of the new colleges for financial aid.”

Miller, along with Polak, chairs a committee charged with preparing the University for the influx of new students.

Johnson’s net worth is $5.6 billion, according to Forbes.