Let's assume the amount is fixed. One approach is to ask to re-frame the position to be better value.
Ask for working hours that effectively pays you more per day, like an 80% contract at the same comp. If they mumble HR and hours, offer to do 4x10 hour days. The magic phrase in corporate is "flexible working". This doesn't solve your comp going up, but you get a 3-day weekend and 52 more holidays a year.
This one even works at intensely bureaucratic organisations like universities. With grants, the amount you can be paid is very fixed, but almost anything else can be approved if three people sign off on it.
Ask for working hours that effectively pays you more per day, like an 80% contract at the same comp. If they mumble HR and hours, offer to do 4x10 hour days. The magic phrase in corporate is "flexible working". This doesn't solve your comp going up, but you get a 3-day weekend and 52 more holidays a year.
This one even works at intensely bureaucratic organisations like universities. With grants, the amount you can be paid is very fixed, but almost anything else can be approved if three people sign off on it.