“It was the Black Monday of 2008″ on Wall Street.

But while classes go on along Sheridan Road, one direct effect of stock market free-falls is on the university’s financial safety cushion.

Northwestern puts a sizable amount of its endowment into stocks, according to Al Cubbage, vice president for university relations. And when stocks fall the farthest they have in two decades, “it has an impact on the endowment,” he said. “At least for that day.”

Cubbage couldn’t elaborate on what that impact means, and the two university officials who might be best-placed to speak about it — Senior Vice President for Business and Finance Eugene Sunshine and Vice President and Chief Investment Officer William McLean — weren’t immediately available for comment on this late-breaking story before the work day ended.

In recent years university officials have spoken of the endowment’s strength.

In the words of President Henry Bienen at his “State of the University” address in February: “Northwestern’s endowment has grown significantly in the past year and now totals approximately $7 billion.” At the time, he said “the result is that Northwestern is in excellent financial health.”

Independent reviews have put it on solid ground as well. A 2007 study said Northwestern had the 11th-highest endowment in the nation.

We’ll update you with more detail when university officials get back to work tomorrow.