
1) Income tax 2) Penalty for the ultrarich 3) Surtax
Found on
https://www.crosswordclues.com/clue/supertax

1) Surtax
Found on
https://www.crosswordclues.com/clue/supertax

• (n.) A tax in addition to the usual or normal tax; specif., in the United Kingdom, an income tax of sixpence for every pound in addition to the normal income tax of one shilling and twopence for every pound, imposed, by the Finance Act of 1909-1910 (c. 8, ss 66, 72), on the amount by which the income of any person exceeds /3,000 when his tot...
Found on
http://thinkexist.com/dictionary/meaning/supertax/

Also called Surtax. An additional tax on something already taxed, e.g. an income above a certain level
Found on
http://www.encyclo.co.uk/local/22643
Su'per·tax` noun [
Super- +
tax .] A tax in addition to the usual or normal tax; specif., in the United Kingdom, an income tax of sixpence for every pound in addition to the normal income tax of one shilling and twopence for every pound, imposed, by the Finance Act of 1909-1910 (c. 8, ss 66...
Found on
http://www.encyclo.co.uk/webster/S/244

Supertax was an additional income tax first levied by the Finance Act of 1909 upon incomes of over 5000 pounds a year at the rate of 6d in the pound for every pound by which the income exceeded 3000 pounds.
Found on
http://www.probertencyclopaedia.com/browse/JS.HTM

a tax in addition to a normal tax, as one upon income above a certain amount. · a surtax.
Found on
https://www.infoplease.com/dictionary/supertax
No exact match found.