Bitcoin (BTC)

Bitcoin (abbreviated BTC) is a decentralized digital currency that can be transferred on a peer-to-peer basis without the need for a bank or other financial intermediary. Created by a pseudonymous person or group known as Satoshi Nakamoto, Bitcoin was described in a white paper published on October 31, 2008, and launched on January 3, 2009, when Nakamoto mined the first block of its blockchain, known as the genesis block.¹² Bitcoin was the first successful implementation of a decentralized digital currency and remains, by a wide margin, the largest cryptocurrency by market capitalization.¹ As of mid-2026, Bitcoin traded in the low-to-mid $60,000s per coin, with a circulating supply of just over 20 million of its capped 21 million total supply and a market capitalization of roughly $1.25–1.3 trillion.³⁴

Overview

Ticker	BTC
Category	Cryptocurrency
Website	http://www.bitcoin.org
Twitter	@bitcoin
Reddit	https://www.reddit.com/r/Bitcoin/

Bitcoin operates on a distributed public ledger called a blockchain, on which transactions are recorded and confirmed by a decentralized network of computers ("nodes") rather than a central authority.¹ New units of the currency are created through a process called mining, in which participants compete to solve a cryptographic puzzle in exchange for the right to add a block of transactions to the chain and receive a block reward.¹ Bitcoin's protocol enforces a hard cap of 21 million coins that will ever be created, with the rate of new issuance cut in half at fixed intervals, an event known as "the halving."¹

Bitcoin was designed as, in Nakamoto's words, a system for "electronic cash" enabling online payments to be sent directly between parties without going through a financial institution.⁵ In practice, its adoption has evolved considerably beyond that original vision: high and volatile transaction fees, slow confirmation times relative to card networks, and Bitcoin's price volatility have limited its use as an everyday medium of exchange, while a "digital gold" narrative — Bitcoin as a scarce, portable store of value — has become the dominant framing among institutional investors, corporate treasuries, and, as of 2025, elements of the U.S. federal government.¹⁶

History

Origins (2008–2009)

The domain name bitcoin.org was registered on August 18, 2008.⁷ On October 31, 2008, a link to a nine-page white paper titled "Bitcoin: A Peer-to-Peer Electronic Cash System," authored under the name Satoshi Nakamoto, was posted to a cryptography mailing list, arriving weeks after the collapse of Lehman Brothers amid the global financial crisis.⁵⁸ The paper proposed combining several pre-existing ideas from cryptography and distributed systems — including proof-of-work schemes such as Hashcash and concepts from earlier proposed digital currencies like b-money — into the first design for a decentralized digital currency that solved the "double-spending" problem without a trusted third party.⁸

Nakamoto mined the genesis block, or "Block 0," on January 3, 2009.² The block embedded a short text string referencing a Times of London headline from that day — "Chancellor on brink of second bailout for banks" — widely interpreted as both a timestamp and a comment on the fragility of the traditional banking system the new currency was designed to circumvent.⁹ The Bitcoin software was released publicly on January 9, 2009, and nine days after the genesis block, Nakamoto sent the first Bitcoin transaction, 10 BTC, to early cryptographer and developer Hal Finney.⁹¹⁰

Early adoption and first exchanges (2009–2013)

In Bitcoin's earliest years, the currency had no established market price and circulated mainly among cryptography enthusiasts. On May 22, 2010, programmer Laszlo Hanyecz paid 10,000 BTC — then worth about $40 — for two pizzas, in what is regarded as the first commercial Bitcoin transaction and is commemorated annually as "Bitcoin Pizza Day."¹⁰ Bitcoin reached price parity with the U.S. dollar in February 2011.¹¹ Satoshi Nakamoto continued to correspond with early developers through 2010 before gradually withdrawing from the project and ceasing communication altogether in April 2011, handing control of the source code repository to other developers; Nakamoto's identity has never been publicly confirmed, and an estimated one million BTC believed to have been mined by Nakamoto in Bitcoin's first year have never moved.¹²

Mt. Gox, a Tokyo-based exchange, became the dominant venue for trading bitcoin during this period.¹³ The currency's early volatility was pronounced: after climbing as high as $31 in mid-2011, its price collapsed to around $2 later that year amid a major security breach at Mt. Gox.¹³ Bitcoin's profile rose considerably in 2013, when its price first surpassed $1,000, the first Bitcoin ATMs were installed, and federal authorities shut down the Silk Road darknet marketplace, seizing roughly 26,000 BTC in the process; the marketplace's founder, Ross Ulbricht, was later sentenced to life in prison, a sentence President Donald Trump commuted via a pardon in January 2025.¹⁴

Mt. Gox collapse and consolidation (2014–2016)

In February 2014, Mt. Gox, by then handling a large share of global Bitcoin trading volume, filed for bankruptcy after disclosing that roughly 850,000 BTC belonging to the exchange and its customers, worth several hundred million dollars at the time, had been lost or stolen.¹⁵ The collapse triggered a prolonged bear market and intensified calls for better custody practices and regulatory oversight across the emerging exchange industry. Bitcoin's first halving had already occurred in November 2012, cutting the block reward from 50 to 25 BTC; a second halving followed in July 2016, reducing the reward to 12.5 BTC.¹⁶

Scaling debate and the 2017 bull run

By the mid-2010s, rising transaction volumes exposed a long-simmering disagreement within the Bitcoin community over how to scale the network: one camp favored increasing Bitcoin's block size limit to accommodate more transactions, while another favored a soft-fork upgrade called Segregated Witness (SegWit), which restructured how transaction data was stored to increase effective capacity without a hard fork.¹ SegWit activated on the Bitcoin network in August 2017. Unable to reach consensus, a group of miners and developers who favored larger blocks split off later that same month to create a separate cryptocurrency, Bitcoin Cash.¹ Despite the schism, Bitcoin's price rose dramatically through 2017 amid a broader wave of public and speculative interest in cryptocurrencies, reaching an all-time high near $20,000 in December 2017 before falling sharply in the subsequent bear market.¹

Institutional era (2020–2022)

Bitcoin's third halving, in May 2020, cut the block reward to 6.25 BTC.¹⁶ The subsequent 2020–2021 period marked a significant shift toward mainstream and institutional acceptance: business intelligence firm MicroStrategy (later renamed Strategy) began accumulating large bitcoin holdings as a corporate treasury strategy starting in August 2020 under CEO Michael Saylor, electric-vehicle maker Tesla purchased $1.5 billion of bitcoin in February 2021, and payments companies including PayPal began supporting cryptocurrency transactions.¹ In September 2021, El Salvador became the first country to adopt Bitcoin as legal tender alongside the U.S. dollar, an initiative championed by President Nayib Bukele and backed by a government-run digital wallet called Chivo.¹⁷ Bitcoin reached a then-record price above $68,000 in November 2021.¹

The period also saw a significant regulatory crackdown in China, which banned cryptocurrency mining and trading outright in 2021, pushing much of the global Bitcoin mining industry to relocate to the United States and other jurisdictions.¹ The broader crypto market subsequently entered a severe downturn in 2022 following the collapse of the Terra/Luna ecosystem and, later that year, the bankruptcy of the FTX exchange, both of which weighed heavily on Bitcoin's price even though Bitcoin itself was not directly implicated in either collapse.¹

Spot ETFs and fourth halving (2024)

In January 2024, the U.S. Securities and Exchange Commission approved the first spot Bitcoin exchange-traded funds in the United States, including products from asset managers BlackRock and Fidelity, allowing investors to gain regulated exposure to Bitcoin's price without directly holding or custodying the asset.¹¹⁸ The approval unlocked substantial new institutional demand and helped drive Bitcoin to new all-time highs of roughly $73,000 in March 2024.¹⁸ Bitcoin's fourth halving occurred that April, cutting the block reward to its current level of 3.125 BTC.¹⁶

Political realignment, Strategic Reserve, and record highs (2024–2025)

Bitcoin's price rose further following Donald Trump's victory in the November 2024 U.S. presidential election, reaching roughly $91,000 amid expectations of a friendlier U.S. regulatory posture toward digital assets, and crossed $100,000 for the first time in early December 2024.¹⁸ On March 6, 2025, Trump signed an executive order establishing a U.S. Strategic Bitcoin Reserve, to be capitalized with bitcoin already held by the federal government as a result of criminal and civil asset forfeitures — an estimated 198,000 to 328,000 BTC across various points in 2025 and 2026 — with a stated policy that the reserve's holdings would not be sold.¹⁹²⁰ A related U.S. Digital Asset Stockpile was created for other forfeited cryptocurrencies.¹⁹ Legislative efforts to codify the reserve into law, including the BITCOIN Act of 2025 and the American Reserve Modernization Act introduced in May 2026, remained pending in Congress as of mid-2026, and interagency disputes between the Treasury and Commerce departments over custody had delayed full implementation.²⁰²¹

Separately, in a reversal of its 2021 policy, El Salvador amended its Bitcoin law in early 2025 as a condition of a $1.4 billion loan agreement with the International Monetary Fund, ending the requirement that merchants accept bitcoin, eliminating its use for tax payments, and winding down the government's Chivo wallet infrastructure, while leaving voluntary private use of bitcoin permitted.²²²³ Central African Republic had separately adopted bitcoin as legal tender in 2022, though with limited practical effect.

Fueled by ETF inflows and the broader shift in U.S. policy, Bitcoin's price climbed through much of 2025, repeatedly setting new all-time highs — around $111,800 in May, $123,000 in July, and $124,000–$125,800 in August — before peaking at approximately $126,200 on October 6, 2025.²⁴²⁵ A sharp correction followed: by February 2026, Bitcoin had fallen to roughly $60,000, a drawdown of more than half from its October peak, before stabilizing in the low-to-mid $60,000s through the first half of 2026.²⁴

Recent regulatory developments (2025–2026)

The period also saw significant U.S. legislative activity affecting the broader digital-asset industry, including passage of the GENIUS Act, a federal framework for stablecoin issuance, in 2025, and continued debate in Congress over the CLARITY Act, proposed market-structure legislation intended to clarify the regulatory treatment of digital assets more broadly; as of mid-2026 the latter had not been enacted.²¹ Several individual U.S. states, including Texas and New Hampshire, established their own state-level strategic bitcoin reserves during this period, while other proposed state reserve bills were vetoed.²⁶

Technical design

Blockchain and proof of work

Bitcoin transactions are grouped into blocks and added to a blockchain — a continuously growing, cryptographically linked chain of blocks maintained collectively by thousands of independently operated network nodes.¹ New blocks are added roughly every ten minutes through a process called mining, in which specialized computer hardware competes to find a numerical solution to a cryptographic puzzle based on the SHA-256 hashing algorithm; the first miner to find a valid solution earns the right to add the next block and collects both the block reward (newly created bitcoin) and the transaction fees paid by users included in that block.¹ The difficulty of this puzzle adjusts automatically roughly every two weeks to keep the average time between blocks close to ten minutes, regardless of how much computing power ("hash rate") is participating in the network; as of mid-2026, the network's aggregate hash rate was estimated at roughly 886 exahashes per second.³

Supply schedule

Bitcoin's protocol caps total issuance at 21 million coins, a limit expected to be reached asymptotically around the year 2140 as block rewards continue to halve.¹ The block reward began at 50 BTC in 2009 and has since halved four times — to 25 BTC in November 2012, 12.5 BTC in July 2016, 6.25 BTC in May 2020, and 3.125 BTC in April 2024 — with the next halving expected around 2028.¹⁶ Each bitcoin is divisible into 100 million subunits known as satoshis, allowing for fractional ownership and transactions well below the value of a single coin.¹

Transactions and wallets

Bitcoin ownership is represented by cryptographic key pairs: a public key (or an address derived from it) to which funds can be sent, and a private key used to authorize spending. Transactions reference and consume previous "unspent transaction outputs" (UTXOs) and create new ones, rather than tracking simple account balances as in a conventional bank ledger.¹ Users typically manage their keys through software or hardware wallets; because control of the private key is equivalent to control of the funds, loss of a private key generally results in permanent loss of the associated bitcoin, with no central authority able to reverse the loss or restore access.

Governance and development

Bitcoin has no formal owner, company, or chief executive; its reference software, Bitcoin Core, is maintained by a loose, decentralized community of volunteer developers, and changes to the protocol are proposed through a public process known as Bitcoin Improvement Proposals (BIPs).¹ Because any changes to consensus rules must be voluntarily adopted by node operators and miners across the network, contentious proposals have historically led to forks — new, separate cryptocurrencies such as Bitcoin Cash — rather than unilateral changes to Bitcoin itself.¹

Economics and markets

Bitcoin's price has historically been highly volatile, moving through repeated cycles of rapid appreciation followed by steep corrections; notable peaks include roughly $1,150 in late 2013, $19,700 in December 2017, $69,000 in November 2021, and approximately $126,200 in October 2025, each followed by drawdowns of 50% or more.¹⁸²⁴ Bitcoin's market capitalization — the product of its price and circulating supply — stood at approximately $1.25 to $1.3 trillion as of July 2026, making it by far the largest cryptocurrency, with the next-largest, Ethereum, valued at roughly one-sixth as much.⁴²⁷

Bitcoin ownership is highly concentrated: research has estimated that a small percentage of holding addresses control a large majority of the circulating supply, a dynamic that can amplify price volatility when large holders ("whales") move significant amounts of bitcoin.²⁸ Since the 2024 approval of U.S. spot ETFs, a growing share of Bitcoin exposure has been intermediated through regulated financial products and corporate treasuries — most prominently Strategy, the largest known corporate holder of bitcoin — rather than through direct self-custody.¹²⁷

Adoption and legal status

Bitcoin's legal status varies considerably by jurisdiction. It is broadly legal and, in many countries, subject to taxation as property or a capital asset, while a smaller number of jurisdictions have imposed outright bans on trading or mining, most notably China in 2021.¹ El Salvador's 2021–2025 experiment with bitcoin as mandatory legal tender — the first of its kind — was ultimately scaled back under IMF pressure, with government surveys finding that the large majority of Salvadorans never used bitcoin for everyday transactions during the period it held that status.¹⁷²³

At a governmental level, adoption has increasingly taken the form of reserve holdings rather than currency status: the U.S. Strategic Bitcoin Reserve, established in 2025, holds bitcoin obtained through law-enforcement forfeiture rather than open-market purchases, and several U.S. states and other national governments have explored or established similar reserve arrangements.¹⁹²⁰²⁶ Institutional adoption has also grown through spot Bitcoin ETFs, which by 2025 had accumulated substantial holdings on behalf of retail and institutional investors, and through direct corporate treasury purchases by publicly traded companies.¹⁸²⁷

Criticism and controversies

Environmental impact

Bitcoin mining's proof-of-work consensus mechanism requires substantial amounts of electricity, and Bitcoin's global energy consumption has drawn sustained criticism from environmental researchers and policymakers; estimates have placed Bitcoin's annualized electricity usage at levels comparable to that of a mid-sized country.¹⁷ Defenders of the network have argued that a growing share of Bitcoin mining relies on stranded, renewable, or otherwise underutilized energy sources, and that comparisons to national energy consumption, while directionally accurate, can be presented in misleading ways.

Illicit use

Bitcoin's pseudonymous (though not fully anonymous) transaction model made it an early payment method of choice for illicit online marketplaces, most notoriously the Silk Road darknet market, which was shut down by U.S. federal authorities in 2013.¹⁴ Blockchain analysis firms and law enforcement agencies have since developed sophisticated techniques for tracing bitcoin transactions, and high-profile prosecutions and asset seizures — including the forfeitures that now fund the U.S. Strategic Bitcoin Reserve — have somewhat diminished, without eliminating, Bitcoin's use in illicit finance.¹⁹

Volatility and investor-protection concerns

Critics, including the International Monetary Fund and various national financial regulators, have repeatedly cited Bitcoin's price volatility, its lack of a central issuing authority to intervene during periods of market stress, and its potential unsuitability as a medium of exchange for populations without existing access to banking services, most notably in the IMF's assessment of El Salvador's legal-tender experiment.²³ Exchange failures and security breaches, from the 2014 Mt. Gox collapse to numerous smaller incidents in the years since, have periodically renewed scrutiny of custodial practices within the broader cryptocurrency industry.¹⁵

References