The reduction of greenhouse gas emissions, the introduction of biodiesel-fueled buses and new “green” building standards were not enough to give Yale the top score in a recent sustainability report.

The University earned a B+ in the inaugural College Sustainability Report Card, released Wednesday by the Sustainable Endowments Institute. The study investigated campus operations and endowments on an A-F scale at the 100 schools with the largest endowments in the United States and Canada, totaling $258 billion. Yale received an A grade in every category except two related to endowments, and only four schools earned a higher overall score than Yale. Administrators said they were pleased that campus sustainability is gaining national attention, but they said the new report may not give an accurate picture of sustainability efforts at the University.

Yale earned a perfect A grade for its efforts in administration, climate change and energy, green building, and shareholder engagement, but received a C for investment priorities and a D in endowment transparency. Two other institutions earned an overall grade of B+, but Harvard, Stanford, Dartmouth and Williams each received an overall A-.

Yale Sustainability Director Julie Newman said she was pleased with the results, particularly for the campus operations categories, in which Yale received top marks. But she said the report’s focus on endowments represents a new line of thinking that is just now beginning to merge with other types of sustainability projects and policies.

“Where we didn’t do so well was what they’re defining as endowment transparency,” she said. “I think it just illustrates that Yale is on a positive trajectory and we still have farther to go. Whether or not they used the correct report card — the jury’s still out on that one.”

The report criticized the University for not investing in renewable energy funds or local community development funds, as well as for keeping secret the endowment’s holdings and its shareholder proxy voting records. Yale describes its investments generally in an annual report, but does not release information about specific holdings. According to the 2006 report released last week, the $18 billion endowment included a 28 percent stake in real assets, a category that includes oil, gas and timber and has performed well in the past, earning returns of more than 17 percent a year.

Like any non-profit institution, Yale has to balance two forces when setting investment priorities that could be considered sustainable, said Robert Repetto, professor of economics and sustainable development at the School of Forestry and Environmental Studies.

“One [issue] that comes up for many, many institutions is where there’s kind of a line between their financial managers and program managers,” he said.

The divide leads administrators on one side of the institution to introduce new sustainable policies and programs at the same time as endowment managers are only looking to maximize profit, he said. Profits gained from investing in oil or gas companies could easily go to support an otherwise sustainable institution.

“The argument is, we make the money and you spend it,” he said.

But a new approach is beginning to find its way into endowment strategy, Repetto said. Some investors are finding substantial profits in industries that focus on sustainability, such as microfinance and renewable energy venture capital.

“Doing well while doing good” is increasingly becoming more possible, he said.

The traditional approach to socially responsible investing is a “negative screen,” said Brad Gentry, lecturer in sustainable investments at the forestry school. Investors remove companies with objectionable interests, such as tobacco companies or oil companies that invest in Sudan, from their portfolios. The newer approach is a “positive screen,” actively seeking out companies that are sustainable, he said.

Though the Yale Investments Office has not made public its policy on seeking out sustainable investments, the body charged with supervising the ethics of Yale’s investments — the Advisory Committee on Investor Responsibility — has focused recently on divestment, such as selling holdings in companies doing business with the Sudanese government. ACIR meetings about how to vote on shareholder resolutions have included some consideration of the environment, however.

The extent to which endowments should be transparent is up for debate, Gentry said. Keeping endowment holdings confidential prevents other investors from copying successful strategies.

“As a beneficiary of the endowment, I’m not sure I’d want them telling everyone,” he said.

In the fall of 2005, Yale pledged to decrease its greenhouse gas emissions to 10 percent below the 1990 level by 2020.