Shadow Economy (Underground Economy)

The shadow economy, also called the underground economy, is economic activity that is deliberately concealed from public authorities. It covers legal goods and services produced off the books to avoid taxes, social security contributions or regulation, such as a builder paid in cash with no invoice, and in broader usage it also includes plainly illegal trade such as drug dealing or smuggling. Because it is hidden, its size can only be estimated.

The term overlaps with the informal economy but is not the same thing. Informality describes work and businesses that fall outside formal arrangements, often because registration is costly or the state is absent; concealment is not the point. The shadow economy is defined by deliberate hiding. It is also unrelated to shadow banking, which refers to lawful credit activity outside the regulated banking system.

Picture a street where most shops ring up every sale on the till and pay tax on it. A few, though, keep a second drawer for cash sales that never reach the books, and a plumber down the road offers a discount if you pay in notes and skip the receipt. Nothing they sell is unusual; they are simply keeping part of their business out of sight.

Add up all those hidden drawers across a country and you have the shadow economy. Officials cannot count it directly, a bit like trying to measure how much water leaks from pipes you cannot see. Instead, they look for clues, such as how much cash people hold or how much electricity is used compared with the business that is officially reported.

There is no single legal definition, and researchers draw the boundary in different places. The economist Friedrich Schneider, whose estimates are the most widely cited, defines the shadow economy narrowly as market-based legal production hidden to avoid taxes, contributions, labour standards or administrative burdens, and leaves out criminal activity. Broader definitions add illegal markets. National statisticians use a related framework, the non-observed economy, set out in a 2002 handbook by the OECD, the IMF and the International Labour Organization, which separates underground, illegal and informal production.

The distinction matters for gross domestic product. Statistical agencies try to include hidden legal activity in GDP, and since 2014 member states of the European Union have also included estimates of some illegal activities, such as drugs and prostitution, under the ESA 2010 accounting standard.

• Tax and contribution burden. High combined taxes on labour make cash work more attractive, a key driver of tax evasion.
• Regulation. Costly licensing, labour rules and paperwork push small firms to operate partly out of view.
• Weak institutions. Corruption, low trust in government and limited enforcement reduce the risk and stigma of concealment.
• Cash use. Widespread use of cash leaves no electronic trail, which is why digital payments are often linked to a smaller hidden sector.
• Economic shocks. Unemployment and falling incomes push people toward undeclared work to make ends meet.

Because hidden activity leaves no records, estimates rely on indirect methods:

• Discrepancy methods. These compare national income with spending, or official labour force figures with survey data, and treat the gap as hidden activity.
• Currency demand approach. Pioneered by Vito Tanzi in the early 1980s, it assumes hidden transactions are paid in cash and estimates how much currency demand exceeds what recorded activity would explain, using data on the money supply.
• Electricity consumption. Changes in power use, which tracks physical output closely, are compared with official GDP growth.
• MIMIC models. The multiple indicators, multiple causes approach treats the shadow economy as an unobserved variable linked to measurable causes, such as tax burden and regulation, and to indicators, such as cash holdings and labour participation.
• Surveys and tax audits. Direct questioning and audit results give lower-bound estimates.

Each method has weaknesses, and results can differ widely for the same country, so estimates are best read as orders of magnitude rather than precise figures.

An IMF working paper by Leandro Medina and Friedrich Schneider, published in 2018, estimated the shadow economy in 158 countries between 1991 and 2015 using MIMIC models. It found an average of 31.9% of GDP over the period. The largest estimates were for Bolivia, at 62.3%, and Zimbabwe, at 60.6%, while the smallest were for Switzerland, at 7.2%, and Austria, at 8.9%. Shadow economies tend to be larger in lower-income countries with weaker tax administration, although sizeable hidden sectors also exist in parts of southern and eastern Europe.

A large shadow economy reduces tax revenue, shifts the burden onto compliant taxpayers and leaves workers without pensions, social security or legal protection. It distorts statistics that guide policy and competes unfairly with firms that obey the rules. Undeclared income, sometimes called black money, can also feed money laundering and informal transfer channels such as hawala. On the other hand, hidden work can provide incomes where formal jobs are scarce, so some economists caution that heavy-handed crackdowns may simply destroy livelihoods.

Governments usually combine enforcement with incentives: simpler registration and lower tax rates for small firms, wider use of electronic payments and e-invoicing, limits on large cash transactions, and better links between social benefits and declared work. Bringing hidden activity into the open is known as formalization, and it is a central theme in research on emerging economies.

• IMF: Shadow Economies Around the World (Working Paper 18/17)
• Organisation for Economic Co-operation and Development (OECD)
• Faisal Khan: Informal Economy Explained