The value of investments made by Jersey's government fell by £95m last year.
The state of public finances was revealed in the 2018 annual accounts, which were published on Wednesday.
Nearly £50m was lost from the Social Security Fund, while £27.5m was labelled as "fruitless" spending on abandoned plans for a new hospital.
Treasury Minister Susie Pinel said the 5% goods and services tax could be raise in the future to cover losses.
Public expenditure outweighed income by £75m for the year.
A total of £635m was received in tax income in 2018 - an increase of 5% - while the value of the Strategic Reserve fell by 4%, and is now worth £807m.
However, unemployment is at the lowest level in nine years, and £8m in extra tax was claimed back by the authorities, to "ensure people pay what they owe".
The government said that while the £95m investment loss "may seem concerning", the long-term investment outlook "remains positive", and the losses were recouped by February.
Jersey's annual report
- There was a 5% increase in pension payments, with £188m paid last year
- Nearly £50m was paid to support people in long-term care, an increase of 4%
- There was a 42% increase in the amount of funded vaccinations, at 40,000
- There were 910 babies delivered at Jersey's hospital
- The police responded to nearly 18,000 incidents during 2018
- The ambulance service attended nearly 10,000 call-outs