Industry WIKI

Cryptocurrency has been used extensively in criminal activities, such as investment and romance scams (often called "pig-butchering"), ransomware payments, thefts and exchange hacks, money laundering and sanctions evasion, darknet-market transactions, and off-chain coercion to obtain private keys. Law enforcement notes that investment fraud and laundering are frequent criminal uses of cr

A cryptocurrency ATM (automated teller machine) or Bitcoin ATM is a kiosk that allows a person to purchase Bitcoin and other cryptocurrencies by using cash or debit card. Some Bitcoin ATMs offer bidirectional functionality, enabling both the purchase of Bitcoin and the sale of Bitcoin for cash. In some cases, Bitcoin ATM providers require users to have an existing account to transact on

A cryptocurrency bubble is a phenomenon where the market increasingly considers the going price of cryptocurrency assets to be inflated against their hypothetical value. The history of cryptocurrency has been marked by several speculative bubbles on a boom to bust cycle.

A cryptocurrency exchange, or a digital currency exchange (DCE), is a business that allows customers to trade cryptocurrencies or digital currencies for other assets, such as conventional fiat money or other digital currencies. Exchanges may accept credit card payments, wire transfers or other forms of payment in exchange for digital currencies or cryptocurrencies. A cryptocurrency excha

Cryptocurrency in Australia refers to the use and regulation of digital currencies such as Bitcoin, Ethereum, and various other altcoins within the country of Australia. Australia has been recognized as a relatively progressive country regarding cryptocurrency adoption and regulation.

Cryptocurrency in Iran has emerged as a pivotal response to economic pressures and global isolation. In 2026, Iran had a total US$7.8 billion cryptocurrency market, and a number of exchanges such as Nobitex. Iran's interest in cryptocurrencies began in 2017 when international sanctions obstructed Iran's access to the global financial markets. In 2019, the government legalized cryptocurr

Cryptocurrency in Nigeria describes the extent of cryptocurrency use, social acceptance and regulation in Nigeria. Nigerians are one of the major global users of cryptocurrencies.

During the second presidency of Donald Trump, cryptocurrency was promoted by Trump and his administration, which took a series of crypto-friendly actions and decisions. His administration appointed crypto-friendly regulators, reduced crypto regulation and dropped investigations into crypto firms and crypto crime. Trump promoted his own cryptocurrency meme coin, $Trump, and maintained sig

A cryptocurrency tumbler or cryptocurrency mixing service is a service that mixes potentially identifiable or "tainted" cryptocurrency funds with others, so as to obscure the trail back to the fund's original source. This is usually done by pooling together source funds from multiple inputs for a large and random period of time, and then spitting them back out to destination addresses. A

A cryptocurrency wallet is a device, physical medium, program or an online service which stores the public and/or private keys for cryptocurrency transactions. In addition to this basic function of storing the keys, a cryptocurrency wallet more often offers the functionality of encrypting and/or signing information. Signing can for example result in executing a smart contract, a cryptocu

CryptoKitties is a blockchain game developed by Canadian studio Dapper Labs. The game allows players to buy, sell, and create non-fungible tokens (NFTs) using Ethereum. These NFTs represent virtual cats. The game's popularity in December 2017 congested the Ethereum network, causing it to reach an all-time high in the number of transactions and slowing it down significantly.

CryptoNote is an application layer protocol designed for use with cryptocurrencies that aims to solve specific problems identified in Bitcoin.

Cryptopia was an international cryptocurrency exchange based in Christchurch, New Zealand. Founded in 2014 by Rob Dawson and Adam Clark, it was among the earliest cryptocurrency services started in the country, and was responsible for launching the first stablecoin pegged to the New Zealand dollar. Cryptopia experienced substantial growth in 2017 from 30,000 users to over 1.4 million by

CryptoPunks is a non-fungible token (NFT) collection on the Ethereum blockchain. The project was launched in June 2017 by the Larva Labs studio, a two-person team consisting of Canadian software developers Matt Hall and John Watkinson. The experimental project was inspired by the London punk scenes, the cyberpunk movement, and electronic music artists Daft Punk. The crypto art blockchain

Currency depreciation is the loss of value of a country's currency with respect to one or more foreign reference currencies, typically in a floating exchange rate system in which no official currency value is maintained. Currency appreciation in the same context is an increase in the value of the currency. Short-term changes in the value of a currency are reflected in changes in the exch

A currency basket is a portfolio of selected currencies with different weightings. A currency basket is commonly used by investors to minimize the risk of currency fluctuations and also governments when setting the market value of a country's currency.

In public finance, a currency board is a mechanism by which a monetary authority is required to maintain a fixed exchange rate with a foreign currency by fully backing the commitment with foreign holdings, or reserves. This policy objective requires the conventional objectives of a central bank to be subordinated to the exchange rate target.

A currency crisis is a type of financial crisis, and is often associated with a real economic crisis. A currency crisis raises the probability of a banking crisis or a default crisis. During a currency crisis the value of foreign denominated debt will rise drastically relative to the declining value of the home currency. Generally doubt exists as to whether a country's central bank has s

A currency detector or currency validator is a device that determines whether notes or coins are genuine or counterfeit. These devices are used in a wide range of automated machines, such as retail kiosks, supermarket self checkout machines, arcade gaming machines, payphones, launderette washing machines, car park ticket machines, automatic fare collection machines, public transport tic

In monetary economics, the currency in circulation in a country is the value of

Currency intervention, also known as foreign exchange market intervention or currency manipulation, is a monetary policy operation. It occurs when a government or central bank buys or sells foreign currency in exchange for its own domestic currency, generally with the intention of influencing the exchange rate and trade policy.

Currency manipulator is a designation applied by United States government authorities, such as the United States Department of the Treasury, to countries that engage in what is called "unfair currency practices" that give them a trade advantage. Such practices may be currency intervention or monetary policy in which a central bank buys or sells foreign currency in exchange for domestic c

Currency packaging includes several forms of packing cash for easy handling and counting. Many systems use standard color-coding or are marked to indicate the amount in the package.

A currency pair is the quotation of the relative value of a currency unit against the unit of another currency in the foreign exchange market. The currency that is used as the reference is called the counter currency, quote currency, or currency and the currency that is quoted in relation is called the base currency or transaction currency.

Currensee (or currensee.com) was a financial services company based in Boston to serve as a social network for foreign exchange (FX, Forex, or currency) traders. The company provided mirror trading services to its clients that allowed them to make trading decisions based on other traders actions. The company was acquired by OANDA in 2013, which decided to close down the service a year la

In macroeconomics and international finance, a country's current account records the value of exports and imports of both goods and services and international transfers of capital. It is one of the two components of the balance of payments, the other being the capital account (also known as the financial account). Current account measures the nation's earnings and spendings abroad and it

Curve is a fintech company who propose the Curve card, a payment card that aggregates multiple payment cards through its accompanying digital wallet mobile app, allowing a user to make payments and withdrawals from a single card. It lets you "switch the bank card you paid with after each transaction is complete." Curve named this feature "Back in time".

A custodian bank, or simply custodian, is a specialized financial institution responsible for providing securities services. It provides post-trade services and solutions for asset owners, asset managers, banks and broker-dealers. Custodial banks do not engage in traditional commercial or retail banking services like lending.

Dahabshiil (Somali: Dahabshiil, Arabic: دهب شيل) is a Somali funds transfer company, headquartered in Dubai, UAE, and is the largest money-transfer business in Africa. Formed in 2004, the firm operates from over 24,000 outlets and employs more than 2,000 people across 126 countries. It provides financial services to international organisations, as well as to both large and small business

DAI (or DAI, formerly Sai or SAI) is a stablecoin token on the Ethereum blockchain which uses smart contracts designed to control supply to keep its value as close to one United States dollar as possible. DAI is maintained and regulated by MakerDAO, a decentralized autonomous organization composed of the owners of its governance token, MKR, who may propose and vote on changes to certain

DAI is a US dollar-pegged stablecoin associated with the Maker system, later linked to the development of the Sky ecosystem. This article introduces its positioning, mechanism, usage verification, and common misconceptions.

In finance, a dark pool (also black pool) is a private forum (alternative trading system or ATS) for trading securities, derivatives, and other financial instruments. Liquidity on these markets is called dark pool liquidity. The bulk of dark pool trades represent large trades by financial institutions that are offered away from public exchanges like the New York Stock Exchange and the NA

Dash is an open source cryptocurrency. It is an altcoin that was forked from the Bitcoin protocol. It is also a decentralized autonomous organization (DAO) run by a subset of its users. It was previously known as Xcoin and Darkcoin.

A data broker is an individual or company that specializes in collecting personal data (such as income, ethnicity, political beliefs, or geolocation data) or data about people, mostly from public records but sometimes sourced privately, and selling or licensing such information to third parties for a variety of uses. Sources, usually Internet-based since the 1990s, may include census and

In finance, a day count convention determines how interest accrues over time for a variety of investments, including bonds, notes, loans, mortgages, medium-term notes, swaps, and forward rate agreements (FRAs). This determines the number of days between two coupon payments, thus calculating the amount transferred on payment dates and also the accrued interest for dates between payments.

A de facto currency is a unit of money that is not legal tender in a country but is treated as such by most of the populace. The United States dollar and the euro are the most common de facto currencies.

Debanking (sometimes spelled de-banking, and also known within the banking industry as de-risking) is the closure of people's or organizations' bank accounts by banks that perceive the account holders to pose a financial, legal, regulatory, or reputational risk to the bank.

A debasement of coinage is the practice of lowering the intrinsic value of coins, especially when used in connection with commodity money, such as gold or silver coins, while continuing to circulate them at face value. A coin is said to be debased if the quantity of gold, silver, copper or nickel in the coin is reduced.

A debit card, also known as a check card, cheque card or bank card, is a payment card that can be used in place of cash to make purchases. The card usually consists of the bank's name, a card number, the cardholder's name, and an expiration date, on either the front or the back. Many new cards now have a chip on them, which allows people to use their card by touch (contactless), or by in

Debt is an obligation that requires one party, the debtor, to pay money borrowed or otherwise withheld from another party, the creditor. Debt may be owed by a sovereign state or country, local government, company, or an individual. Commercial debt is generally subject to contractual terms regarding the amount and timing of repayments of principal and interest. Loans, bonds, notes, and mo

A debt buyer is a company, sometimes a collection agency, a private debt collection law firm, or a private investor, that purchases delinquent or charged-off debts from a creditor or lender for a percentage of the face value of the debt based on the potential collectibility of the accounts. The debt buyer can then collect on its own, utilize the services of a third-party collection agenc

Debt intolerance is a term referring to the inability of emerging markets to manage levels of external debt that, under the same circumstances, would be manageable for developed countries, making a direct analogy to lactose-intolerant individuals. It was coined by Carmen Reinhart, Kenneth Rogoff and Miguel Savastano.

A company's debt-to-equity ratio (D/E) is a financial ratio indicating the relative proportion of shareholders' equity and debt used to finance the company's assets. Closely related to leveraging, the ratio is also known as risk ratio, gearing ratio or leverage ratio. The two components are often taken from the firm's balance sheet or statement of financial position (so-called book value

In the consumer mortgage industry, debt-to-income ratio (DTI) is the percentage of a consumer's monthly gross income that goes toward paying debts. (Speaking precisely, DTIs often cover more than just debts; they can include principal, taxes, fees, and insurance premiums as well. Nevertheless, the term is a set phrase that serves as a convenient, well-understood shorthand.) There are two

A decentralised application (DApp, dApp, Dapp, or dapp) is an application that can operate autonomously, typically through the use of smart contracts, that run on a blockchain or other distributed ledger system. DApps provide a function or utility to their users with less human intervention. Control over some DApps is distributed over holders of tokens that represent ownership over a DAp

A decentralized autonomous organization (DAO) is a software system for organization of other computer programs handled through a decentralized ledger technology like a blockchain. These systems are used most commonly to handle voting and finances, among other processes. The precise legal status of this type of organization system is unclear.

Decentralized finance (often stylized as DeFi) provides financial instruments and services through smart contracts on a programmable, permissionless blockchain. This approach reduces the need for intermediaries such as brokerages, exchanges, or banks. DeFi platforms enable users to lend or borrow funds, speculate on asset price movements using derivatives, trade cryptocurrencies, insure

Deferred financing costs or debt issuance costs is an accounting concept meaning costs associated with issuing debt (loans and bonds), such as various fees and commissions paid to investment banks, law firms, auditors, regulators, and so on. Since these payments do not generate future benefits, they are treated as a contra debt account. The costs are capitalized, reflected in the balance

In economics, deflation is an increase in the real value of the monetary unit of account, as reflected in a decrease in the general price level of goods and services exchanged, measurable by broad price indices.

At the micro-economic level, deleveraging refers to the reduction of the leverage ratio, or the percentage of debt in the balance sheet of a single economic entity, such as a household or a firm. It is the opposite of leveraging, which is the practice of borrowing money to acquire assets and multiply gains and losses.

Demand deposits or checkbook money are funds held in demand accounts in commercial banks. These account balances are usually considered money and form the greater part of the narrowly defined money supply of a country. Simply put, these are deposits in the bank that can be withdrawn on demand, without any prior notice.

In economics, a demand shock is a sudden event that increases or decreases demand for goods or services temporarily.

The Department of Finance is a department of the Australian Government that is responsible for assisting the government across a wide range of policy areas to ensure its outcomes are met, particularly with regard to expenditure, fiscal management and operations of government.

The Department of Finance (DoF, Irish: An Roinn Airgeadais, Ulster-Scots: Männystrie o Siller) is a devolved Northern Ireland government department in the Northern Ireland Executive. The minister with overall responsibility for the department is the Minister for Finance. The incumbent Minister is John O'Dowd.

Papua New Guinea's Department of Finance is responsible for the "protection of public money" in Papua New Guinea (PNG). It aims to improve "the transparency and accountability of the accounting and financial reporting and their frameworks" in the country. The department is led by a Minister of Finance. The headquarters of the department are at Vulupindi Haus, Waigani.

A deposit account is a bank account maintained by a financial institution in which a customer can deposit and withdraw money. Deposit accounts can be savings accounts, current accounts or any of several other types of accounts explained below.

Deposit insurance, deposit protection or deposit guarantee is a measure implemented in many countries to protect bank depositors, in full or in part, from losses caused by a bank's inability to pay its debts when due. Deposit insurance or deposit guarantee systems are one component of a financial system safety net that promotes financial stability, and are typically integrated with bank

The Deposit Insurance Agency (DIA; Russian: Агентство по страхованию вкладов, АСВ) is a Russian state corporation (non-profit organization) established in January 2004 to manage operation of the deposit insurance system in the Russian Federation. DIA pays insurance compensations to depositors of failed banks. DIA also exercises bankruptcy administrator functions of insolvent banks, non–g

Deposit risk is a type of liquidity risk of a financial institution that is generated by deposits either with defined maturity dates (then such deposits are called 'time' or 'term' deposits) or without defined maturity dates (then such deposits are called 'demand' or 'non-maturity' deposits).

In finance, a derivative is a contract between a buyer and a seller. The derivative can take various forms, depending on the transaction, but every derivative has the following four elements:

Devaynes v Noble (1816) 35 ER 781, best known for the claim contained in Clayton's case, created a rule, or more precisely common law presumption, in relation to the distribution of money from a bank account. The rule is based upon the deceptively simple notion of first-in, first-out to determine the effect of payments from an account, and normally applies in English Law in the absence o

Digital Currency Group Inc. (DCG) is an American investment company focusing on the digital currency market and decentralized technologies. It is headquartered in Stamford, Connecticut. The subsidiaries include Grayscale Investments, Yuma, Foundry, Luno, and Fortitude Mining. It also formerly owned the now-inactive Genesis Global Holdco and CoinDesk.

Digital gold currency (DGC) is a form of digital currency based on mass units of gold. The typical unit of account for such currency is linked to grams or troy ounces of gold, although other units such as the gold dinar are sometimes used. DGCs are backed by gold through unallocated or allocated gold storage. A digital gold currency could be a kind of representative money if it is exchan

The digital ruble (Russian: цифровой рубль, romanized: tsifrovoy rubl') is a central bank digital currency (CBDC) issued by the Central Bank of Russia (Bank of Russia). It represents the third official form of the Russian national currency alongside cash and commercial bank deposits, with all forms legally equivalent and exchangeable at par.

The dinar (, ) is the name of the principal currency unit in several countries near the Mediterranean Sea, with a more widespread historical use. The English word "dinar" is the transliteration of the Arabic دينار (dīnār), which was possibly borrowed via the Syriac dīnarā from the Latin dēnārius.

Diners Club International Ltd. (DCI), founded as Diners Club, is a payment network owned by Capital One. Diners Club and its franchises are accepted in over 200 countries and territories. Card issuers operating in approximately 45 countries have exclusive individual licenses to issue cards on the Diners Club network in a given country.

A direct bank (sometimes called a branch-less bank or virtual bank) is a bank that offers its services only via the Internet, mobile app, email, and other electronic means, often including telephone, online chat, and mobile check deposit. A direct bank has no branch network. It may offer access to an independent banking agent network and may also provide access via ATMs (often through in

A direct debit or direct withdrawal is a mandated financial transaction whereby a payer authorizes a payee to draw varying recurring amounts directly from the payer's bank account, commonly used for billing utilities, loans, and subscriptions. Formally, the organisation that calls for the funds ("the payee") instructs their bank to collect (i.e., debit) an amount directly from another's

Direct market access (DMA) in financial markets is the electronic trading infrastructure that gives investors wishing to trade in financial instruments a way to interact with the order book of an exchange. Normally, trading on the order book is restricted to broker-dealers and market making firms that are members of the exchange. Using DMA, investment companies (also known as buy side fi

A direct public offering (DPO) is a method by which a company can offer an investment opportunity directly to the public.

Discount policy is a policy tool used by central banks to control the money in circulation by raising or lowering interest rates.

The discount window is an instrument of monetary policy (usually controlled by central banks) that allows eligible institutions to borrow money from the central bank, usually on a short-term basis, to meet temporary shortages of liquidity caused by internal or external disruptions.

The Disney Dining Plan is a prepaid meal package that guests staying at Walt Disney World hotels can purchase to receive discounts of up to 30% on food in the complex. It was first introduced in 2005 and has developed in complexity over time, so there are now many different plan forms. The Disney Dining Plan allows guests to eat at park restaurants without needing to have cash on their p

A distributed ledger (also called a shared ledger or distributed ledger technology or DLT) is a system whereby replicated, shared, and synchronized digital data is geographically spread (distributed) across many sites, countries, or institutions. In contrast to a centralized database, a distributed ledger does not require a central administrator, and consequently does not have a single (

Distributed ledger technology law ("DLT law") (also called blockchain law, Lex Cryptographia or algorithmic legal order) is a loosely defined emerging field of law resulting from the recent use of distributed ledger technology in business and government. Those smart contracts which were created through interaction of lawyers and developers and are intended to also be enforceable legal co

In financial economics, the dividend discount model (DDM) is a method of valuing the price of a company's capital stock or business value based on the assertion that intrinsic value is determined by the sum of future cash flows from dividend payments to shareholders, discounted back to their present value. The constant-growth form of the DDM is sometimes referred to as the Gordon growth

The dividend yield of a share is the ratio of annualised cash dividends to the share's current market price. It is usually expressed as a percentage and is commonly calculated by dividing the annual dividend per share by the current share price.

Domestic liability dollarization (DLD) pertains to the denomination of banking system deposits and loaning in a currency other than that of the country in which they are held. DLD does not refer exclusively to denomination in US dollars, as DLD encompasses accounts denominated in internationally traded "hard" currencies such as the British pound sterling, the Swiss franc, the Japanese ye

Double-spending is the unauthorized spending of the same money (either digital or conventional) more than once. As with counterfeit money, double-spending leads to supply inflation by creating a new amount of copied currency that did not previously exist. It can also devalue the currency and diminish user trust in the currency.

The drawdown is the measure of the decline from a historical peak in some variable (typically the cumulative profit or total open equity of a financial trading strategy).

In economics, a dual exchange rate is the occurrence of two different values of a currency for different sets of monetary transactions. One of the most common types consists of a government setting one exchange rate for specific transactions involving foreign exchange and another exchange rate governing other transactions.

Dumbell's Bank was a bank in the Isle of Man. The bank's insolvency in 1900, known as Black Saturday and referred to in the Isle of Man as the Dumbell's Bank Crash, resulted in a run on the bank with many individuals losing their life savings and the ruin of numerous local businesses causing poverty, depression and bankruptcy. The effects were profound and lasted for a considerable numbe

Dupont analysis is a tool used in financial analysis, where return on equity (ROE) is separated into its component parts.

In finance, duration is a measure of how the price of a fixed-income instrument responds to a change in interest rates. It is used to compare rate risk across bonds and to construct hedges, and is often paired with convexity and the price value of a basis point. Duration-based estimates work best for small, parallel shifts in the yield curve.

In finance and accounting, and particularly in asset and liability management (ALM), the duration gap measures how well matched are the timings of cash inflows (from assets) and cash outflows (from liabilities), and is then one of the primary asset–liability mismatches considered in the ALM process.

The Durbin amendment, implemented by Regulation II, is a provision of United States federal law, 15 U.S.C. § 1693o-2, that requires the Federal Reserve to limit fees charged to retailers for debit card processing. It was passed as part of the Dodd–Frank financial reform legislation in 2010, as a last-minute addition by Dick Durbin, a senator from Illinois, after whom the amendment is nam

Dynamic currency conversion (DCC) or cardholder preferred currency (CPC) is a process whereby the amount of a credit card transaction is converted at the point of sale, ATM or internet to the currency of the card's country of issue. DCC is generally provided by third party operators in association with the merchant, and not by a card issuer. Card issuers permit DCC operators to offer DCC

e-Bullion was an Internet-based digital gold currency founded by Jim and Pamela Fayed of Moorpark, California, as part of their Goldfinger Coin & Bullion group of companies. The company was incorporated in 2000 and launched on July 4, 2001. Similar to competing systems such as e-gold, e-Bullion allowed for the instant transfer of gold and silver between user accounts. e-Bullion was a reg

An e-commerce payment system (or an electronic payment system) facilitates the acceptance of electronic payment for offline transfer, also known as a subcomponent of electronic data interchange (EDI). E-commerce payment systems have become increasingly popular due to the widespread use of internet-based shopping and banking.

E-gold or eGold was a digital gold currency operated by Gold & Silver Reserve Inc. (G&SR) that allowed users to make payments, which it called "spends", in grams of gold, silver, and other precious metals. E-gold was launched in 1996 and grew to five million accounts by 2009, when transfers were suspended due to legal issues. At its peak in 2006, e-gold processed more than US$2 billion w

E-ZPass Interagency Group (E-ZPass Group trade name and E-ZPass product brand) is an electronic toll collection system used on toll roads, toll bridges, and toll tunnels in the eastern half of the United States. The group itself is composed of several states' member agencies, which share the same technology and allow travelers to use the same transponder on toll facilities throughout the

Early American currency went through several stages of development during the colonial and post-Revolutionary history of the United States. John Hull was authorized by the Massachusetts legislature to make the earliest coinage of the colony (the willow, the oak, and the pine tree shilling) in 1652.

The early history of private equity relates to one of the major periods in the history of private equity and venture capital. Within the broader private equity industry, two distinct sub-industries, leveraged buyouts and venture capital experienced growth along parallel although interrelated tracks.

EarnIn is an American earnings management company that provides earned wage access services and other financial and payroll-related services.

Earnings before interest, taxes, depreciation, and amortization, commonly known as EBITDA ( EE-bit-dah, EB-it-dah), is a measure of a company's profitability of the operating business only, before any effects of indebtedness, state-mandated payments, and costs required to maintain its asset base. It is derived by subtracting from revenues all costs of the operating business (e.g., wages,

An earnings call is a teleconference or webcast in which a public company discusses its financial results for a reporting period, often providing earnings guidance for future performance. The term stems from earnings per share (EPS), calculated as net income (the "bottom line" on the income statement divided by the number of outstanding shares). Earnings calls typically accompany a press

Earnings per share (EPS) is the monetary value of earnings per outstanding share of common stock for a company during a defined period of time, often a year. It is a key measure of corporate profitability, focusing on the interests of the company's owners (shareholders), and is commonly used to price stocks.

Earning yield is the quotient of earnings per share (E), divided by the share price (P), giving E/P. It is the reciprocal of the P/E ratio.

EasyGo is a joint venture between Norway, Sweden, Denmark and Austria, that enables use of a single electronic toll tag on toll roads, ferries and bridges in all the member countries. The purpose of EasyGo is to enable the use of one OBE for payment when driving through any toll facility one might encounter on the way through Northern Europe and Austria.

An economic expansion is an upturn in the level of economic activity and of the goods and services available. It is a finite period of growth, often measured by a rise in real GDP, that marks a reversal from a previous period, for example, while recovering from a recession. The explanation of fluctuations in aggregate economic activity between expansions and contractions ("booms" and "bu