In 1945 and 1946, hyperinflation caused the issuance of notes up to 100 million b.-pengő (100 quintillion or 1020 pengő). During the hyperinflation, note designs were reused, changing the colour and replacing the word pengő with first milpengő, then b.-pengő, to generate higher denominations. The largest denomination produced was 100 million b.-pengő (100 quintillion or 1020 pengő). The note was initially worth about US$ 0.20. Notes of one milliard b.-pengő (one sextillion or 1021 pengő) were printed but never issued.
The introduction of adópengő was an attempt to keep inflation amongst limits, however, it could only slow down somewhat but did not stop the depreciation of the currency. Bonds were issued by the Ministry of Finance in denominations between 10 000 and 100 000 000 adópengő. These simple design notes on low-quality paper became legal currency in the last months of the Hyperinflation almost completely replacing pengő. The enormous amount of paper consumed during the production of the inflation pengő notes caused a shortage of good quality security paper; this hindered the production of forint banknotes.
Notes of one milliard b.-pengő (one sextillion or 1021 pengő) were printed but never issued