Harberger tax

Owners self-assess the value of their property, pay a tax on that value and must sell to anyone willing to pay it.

Arnold Harberger described self-assessment in the 1960s; Posner and Weyl's Radical Markets (2018) revived it as a 'common ownership self-assessed tax' that discourages holding assets idle and funds public goods.

• Sun Yat-sen proposed self-assessed land values in early 20th-century China.
• Several digital-art and on-chain registries have trialled always-for-sale ownership.

Forced sale undermines the security people need to invest in homes and businesses, and may favour the wealthy who can outbid. Valuation of unique assets is hard.

No jurisdiction applies a full Harberger tax to land or housing. It remains a theoretical proposal with small digital trials.