Zakaat on a government bursary

Q: If a person is studying at a university and is funded by a government bursary as well as gets discount by the university but the government bursary only pays fees in January or so, so the student is in debt to the university by the end of year in December, but because the government pays the bursary in January and due to the discount that the university gives there is still an amount left over with the university on the students financial statement stating that the university owes the student some money. So all the years of studies goes on in this way where the excess money left over gets used up completely during the course of the year for fees but by the end of the year the student is in debt and the following year the bursary pays it out and now the university owes the student.

Does the student have to pay zakaat on the left over amount that's reflecting on his financial statement? (Despite this money getting used up during the course of the year completely and despite him not having any access to it) or does he only have to pay zakaat on the money that he has in his possession?