LONDON (Reuters) -The triple A ratings of Harvard and other U.S. Ivy League colleges should be able to withstand all but the most extreme and coordinated tax and endowment fund threats posed by Donald Trump's U.S. administration, S&P Global has said.

Trump and Harvard have been battling over the president's allegations of on-campus anti-Semitism. The White House has terminated billions of dollars of grants and moved to ban Harvard from admitting international students.

The response from the oldest and richest university in the U.S. - which also has over $8 billion worth of bonds - has been to sue.

Harvard won an injunction on the enrolment issue last week. Trump also signalled a resolution might be reached soon, but focus on the financial ramifications - and its triple A rating - remains intense given his threats to also strip Harvard of its tax-exempt status and ratchet up endowment taxes from 1.4% to as high as 21%.

Jessica Goldman, S&P's lead analyst on Harvard, said that despite all the pressures, Harvard's strong finances and flexibility to bolster its income streams if needed, meant its top tier rating should remain in place.

Harvard "is one of our strongest ratings, so it would really take a confluence of these issues to impact the rating," Goldman told Reuters.

"It wouldn't just take one year of weaker operations... it would take a myriad of those metrics declining significantly."

S&P's lead analyst on the overall U.S. higher education sector, Jessica Wood, added that a highly selective institution like Harvard could easily compensate for any ban on international students by filling the places with full-paying U.S. students.

More broadly though, some colleges have started to see an impact on their ratings. Last month, for example, S&P put triple A-rated Swarthmore College on a "negative outlook" - effectively a downgrade warning - after the school took on more debt.

"What is interesting is that the government policies (being proposed) have more potential to impact the higher-rated universities," Wood said.

Less-prestigious institutions might not be as hurt by the latest threats, yet they face other pressures.

With declining demographics, universities expect fewer students to apply for admissions in coming years.

Only around 8% of the hundreds of higher education U.S. institutions S&P rates are in the "junk" grade category. However, there are roughly another 27% just above that threshold, in the BBB band.

Early September will give S&P a better picture of enrolments, Wood said, adding that by then there should also be more clarity on Trump's tax plans.