Many students are still waiting for university places to be confirmed after the proportion of A-levels awarded at least an A fell for the first time in more than 20 years.
This summer's A-level results reveal that 26.6% of exams were awarded an A or A*, down from 27% in 2011 - a drop of 0.4%.
It is believed to be the biggest fall on record for A-levels. The A* to A pass rate stalled at 27% last year, and the last time it fell was between 1990 and 1991.
Some 7.9% of exams have been awarded an A*, a drop from 8.2% last year. But the overall A* to E pass rate has risen to 98% from 97.8%.
Exam chiefs insisted that the drop is down to more students, and a broader range of candidates, taking A-levels.
Andrew Hall, chief executive of AQA, said while the national cohort of 18-year-olds eligible to take A-levels was down from last year, the number of them sitting the exams had risen. He said: "It's very clear there's a different cohort profile which led us to believe we'd get what we got - which is a change in outcomes."
Ziggy Liaquat, managing director of the Edexcel board, argued that the fall was "marginal", adding "the standard needed to reach an A grade has not changed".
The drop comes amid continuing attempts by the exams regulator Ofqual to tackle grade inflation. It has told exam boards they will be asked to justify results that differ widely from previous years.
As of 3.50pm, 358,356 applicants had university places confirmed, down from 391,893 who had secured places at the same point last year, Ucas figures show. A further 3,699 have already found a place through clearing, up from 3,376 in 2011. Thirty-four students have found spots through adjustment - the process that allows applicants who have done better than expected to "trade up" to a different university. At this point last summer, just 12 had found a place this way.
Some 94,812 students are still waiting on decisions compared with 88,471 last year, the figures show. And 164,749 students are eligible for clearing, fewer than last year when 191,833 could enter the process.