Stock trading now happens so quickly that the underlying transaction is easy to forget. An investor opens an app, types a company name, enters a quantity and presses buy. The order can reach a market in a fraction of a second. Prices update continuously, charts are available free of charge and investors with relatively small accounts can purchase pieces of companies worth hundreds of billions of dollars. None of this resembles the markets in which stock trading began.
The basic idea is much older. Companies needed capital for projects that were too large or risky for one merchant to finance. Investors were willing to provide that capital if ownership could be divided and their interest could later be sold. Once company shares became transferable, a secondary market became possible. Investors no longer had to wait for a business to finish its commercial life before recovering their money. They could sell their ownership claim to somebody else.
That simple change created the foundation of modern stock trading. The following four centuries added exchanges, brokers, telegraphs, ticker machines, regulation, computers and smartphones. The technology changed almost beyond recognition. The economic transaction did not. One investor still transfers an ownership claim to another at an agreed price.
Tradable Company Shares Created the Stock Market
The history of stock trading is closely connected with the development of the joint stock company. Earlier businesses could raise money from partners or lenders, but large international commercial ventures required far more capital than most individual merchants could provide. Ships had to be built and supplied, crews paid and voyages financed for long periods before cargo could return.
The Dutch East India Company, usually known by its Dutch initials VOC, became a defining development. In 1602, investors supplied permanent capital to the company in return for transferable shares. Euronext, which now operates the Amsterdam exchange, traces the modern Amsterdam securities market to the VOC share issue and describes Amsterdam as the world’s oldest functioning stock exchange. Euronext’s history of the Amsterdam exchange identifies the 1602 VOC issue as a central event in the creation of an organised share market.
Transferability was the important part for stock traders. The company could retain the original investment while one shareholder sold their economic interest to another person. A long lived enterprise and a shorter investor holding period could now exist simultaneously.
That distinction remains central today. When a company sells shares during an initial public offering, capital moves into the corporate financing system. When investors later trade those shares with each other, most of the transaction occurs in the secondary market. The company continues operating regardless of whether an individual shareholder stays for twenty years or sells tomorrow morning.
Amsterdam Developed an Early Secondary Share Market
Once VOC shares could change hands, trading did not remain a simple administrative transfer between passive investors. Buyers and sellers developed different opinions about future profits, dividends and commercial risks. A secondary market began assigning changing prices to those expectations.
Amsterdam consequently demonstrated many characteristics still found in modern stock markets. Investors could speculate on price movement, brokers could arrange transactions and liquidity allowed investors to convert ownership interests back into cash without asking the company itself to repay them.
Liquidity changed the attraction of equity ownership. Providing capital to a business becomes easier to justify when the investor knows the position can potentially be sold. The buyer accepts the ownership claim, while the company keeps using its capital. That relationship between permanent corporate capital and transferable personal ownership became one of the great advantages of public equity markets.
Early trading obviously lacked modern protections. Information moved slowly, record keeping was manual and market participants were far fewer. Yet the essential behaviour was surprisingly recognisable. Investors responded to information, disagreed about valuation and traded based on different expectations of the future.
The technology around the market would change repeatedly. The reason two investors might disagree about the value of the same share did not.
London Stock Trading Grew Around Coffee Houses
London’s early securities market developed in a setting that sounds more social than financial: coffee houses.
During the seventeenth century, London’s coffee houses became meeting places where merchants, brokers and investors exchanged information and arranged transactions. Without electronic quotations or a central database of available sellers, being physically present where other market participants gathered was commercially useful.
The London Stock Exchange dates an important step to 1698, when John Castaing began publishing a list of stock, commodity and currency prices at Jonathan’s Coffee House. The exchange’s official history records the opening of a more formal trading club known as “The Stock Exchange” in Sweeting’s Alley in 1773, followed by a purpose built exchange at Capel Court in 1802. London Stock Exchange history documents this progression from coffee house quotations to a formal exchange.
The importance of brokers became obvious during this period. Investors outside the main financial centre could not see every available price or locate counterparties easily. A broker’s network and knowledge of current market conditions were valuable services.
For much of the next two centuries, stock trading remained closely connected to privileged access to information and trading venues.
Brokers Became the Human Network Behind the Market
A modern investor sees a consolidated order ticket and price quote. Earlier investors relied on people.
A customer wanting to purchase shares generally instructed a broker, who interacted with other market professionals until a seller was located. Brokers knew where securities could be bought and sold, what prices were being discussed and which other brokers were active in particular stocks.
That made stock trading partly a relationship business. A broker did much more than transmit an instruction. The broker could provide prices, research and market information before finding another participant willing to complete the transaction.
Physical location reinforced this advantage. Someone standing in an exchange building could observe changing demand before an investor many miles away learned that prices had moved. The communication delay could be hours or days.
The history of trading technology can therefore be viewed partly as a long reduction in the value of physical proximity. Newspapers distributed prices beyond the exchange. Telegraphs reduced communication delays. Telephones allowed orders to travel remotely. Computers distributed prices electronically, and the internet eventually put market access directly in front of the customer.
Each step removed another reason for the investor and broker to be in the same place.
New York Brokers Created Their Own Organised Market
American securities trading expanded after independence as federal and state governments issued debt and companies raised capital. New York brokers responded by organising their own trading relationships.
On May 17, 1792, twenty four brokers signed what became known as the Buttonwood Agreement. The New York Stock Exchange regards the agreement as its founding event. The brokers established rules governing transactions and agreed commission arrangements, creating a trusted group through which securities could be bought and sold. NYSE’s official history records the Buttonwood Agreement and the gradual expansion of securities trading as the United States grew.
Government bonds were important early securities, followed by shares in banks, insurance companies and transport businesses. As American industrialisation accelerated, railroads became major users of public capital. Later generations brought utilities, manufacturers, retailers, technology businesses and thousands of other public companies.
The exchange evolved along with them. By the end of the US Civil War, the NYSE says more than 300 stocks and bonds were being traded. In 1865, it moved into a permanent location on part of its present Broad Street site.
Stock trading was becoming an institution rather than a collection of occasional transactions.
The Trading Floor Became the Centre of Stock Price Discovery
The physical trading floor became one of the enduring images of twentieth century finance. Brokers gathered at designated areas, orders were communicated verbally and transactions were written down before being processed through brokerage operations.
NYSE history describes the development of continuous trading, with securities assigned to trading posts and brokers moving across the floor to transact in different stocks.
This system could process remarkably large amounts of business for a human market, but access remained restricted. Exchange membership had economic value because ordinary customers could not walk onto the floor and execute orders personally. They needed brokerage firms connected to exchange members.
The market therefore had several layers. The customer spoke with the brokerage firm. The broker communicated the order toward the floor. A floor broker interacted with other market participants, and the completed transaction worked its way back through the system.
Execution could seem fast by contemporary standards, but it was fundamentally manual. Paper records, telephone calls and human specialists connected the transaction.
Computers would eventually compress those layers, although they did not eliminate the broker’s legal and financial role.
The Telegraph Changed Stock Trading Before Computers Arrived
One of the first major technological shocks to stock trading was the telegraph.
Before electronic communication, information moved roughly as fast as a person, horse, train or ship could carry it. Financial markets in different cities could therefore operate with meaningful information gaps.
The telegraph allowed quotations and orders to travel electronically. The stock ticker then made continuous market data easier to distribute. The NYSE dates the introduction of its stock ticker to 1867 and credits it with rapidly transmitting market information around the United States.
This began changing what it meant to be close to the market. An investor did not have to stand outside the exchange to receive relatively current prices. Brokerage offices could receive ticker information and service customers much farther from New York.
The telephone extended this process. Customers could call brokers rather than visiting an office personally, and brokerage firms built branch networks capable of collecting orders from across the country.
The market remained controlled by human intermediaries, but the information gap between Wall Street and everybody else was narrowing.
Public Stock Markets Became Central to Industrial Capital
As stock exchanges matured, public equity became an important way of financing large corporations.
Railroads provide an obvious nineteenth century example. Building networks over vast distances required more capital than most founders could supply personally. Public markets helped distribute ownership across many investors while giving existing shareholders an avenue for selling.
The same mechanism later financed manufacturers, utilities and many of the companies that shaped twentieth century consumer economies. Stock trading therefore served two related functions. Primary equity markets supplied businesses with capital, while secondary trading made those ownership claims easier for investors to hold.
This distinction is worth remembering because secondary trading is often dismissed as speculation disconnected from productive business. In practice, liquid trading helps support primary capital formation. Investors are generally more willing to commit capital to a company when they know that ownership can later be transferred.
The relationship is not perfect. Stock markets also produce speculative excess and periods when prices separate dramatically from business fundamentals. Yet a functioning secondary market makes equity ownership more flexible, which can reduce the cost of raising permanent capital.
The 1929 Crash Changed Securities Regulation
Stock trading expanded quickly during the 1920s. Speculation, credit and rising public participation contributed to a boom that ended dramatically with the 1929 market crash. The economic collapse that followed transformed the regulatory structure of American securities markets.
Congress passed the Securities Act of 1933 to establish disclosure requirements for public securities offerings. The Securities Exchange Act followed in 1934 and created the Securities and Exchange Commission. The SEC states that the 1934 Act gave it broad authority over exchanges, brokerage firms, clearing agencies and other securities market institutions. SEC statutes and regulations describes the Act as the basis of federal oversight of the secondary securities market.
The exchanges did not disappear as self governing organisations. Instead, their rule systems became part of a federal oversight structure. The SEC has described the 1934 framework as combining exchange self regulation with federal supervision.
This was a major change in stock trading history. Markets had developed largely through private associations and exchange rules. After the 1930s, federal regulation became a permanent part of US market structure.
Brokerage Failures Produced Another Layer of Investor Protection
Regulation did not eliminate operational risk. During the late 1960s, a surge in stock trading created what became known as the paperwork crisis.
Brokerage firms struggled to process the growing number of transactions using systems still heavily dependent on manual records. A number of firms failed, merged or were acquired. The problem demonstrated that investors faced risk not only from falling stock prices but also from the institutions holding their securities.
Congress responded with the Securities Investor Protection Act of 1970, creating the Securities Investor Protection Corporation. SIPC explains that its purpose is to protect eligible customers against certain losses when a broker dealer fails financially and customer assets are missing. SIPC history traces the organisation to the brokerage failures preceding the 1970 legislation.
SIPC protection is not insurance against market losses. A share bought for $100 can still fall to $20 without creating a SIPC claim. The protection concerns the custody relationship between customers and failed brokerage firms.
That distinction became increasingly important as brokers evolved into large custodians of household investment assets.
Fixed Commissions Protected the Traditional Brokerage Model
For much of US stock market history, brokerage commissions were not freely competitive.
The Buttonwood Agreement itself contained commission arrangements, and fixed minimum exchange commissions survived in various forms for generations. That meant brokers could compete on service and relationships without facing unrestricted price competition on every transaction.
The structure changed on May 1, 1975, a date that became known as May Day in securities markets. Fixed minimum commission rates were eliminated. An SEC speech from that year noted that the broad system of fixed commissions could be traced back to the Buttonwood brokers and had endured for more than 175 years. SEC discussion of May Day describes the removal of fixed retail commissions as a major structural change.
Price competition could now operate much more freely.
This helped create the discount broker. Customers who did not require extensive investment advice could pay less for straightforward execution. The broker was gradually becoming divisible into two services: advice and transaction processing.
That separation prepared the market for online trading.
London Experienced Its Own Brokerage Revolution
The British market underwent a comparable structural break in 1986.
London’s “Big Bang” reforms abolished old market conventions and accelerated the move toward electronic dealing. The London Stock Exchange says the market was deregulated in 1986, with computerised trading replacing the older floor-based model and trading activity increasing sharply. In 1997, its SETS system introduced automatic matching of orders. London Stock Exchange history records both transitions.
The Bank of England reported shortly after Big Bang that reforms had increased competition, reduced transaction costs and improved liquidity in the UK equity market. It also noted the entry of larger British and international banks and securities companies into exchange membership. Bank of England’s review of the reforms describes the structural changes following October 27, 1986.
Stock exchanges on both sides of the Atlantic were moving away from protected brokerage structures and toward greater competition, larger firms and electronic systems.
Nasdaq Put Stock Quotations Onto Computers
The computerisation of stock trading did not happen overnight. One of the defining early steps came with Nasdaq.
Nasdaq began operations on February 8, 1971 as the National Association of Securities Dealers Automated Quotations system. Nasdaq describes the original platform as the world’s first fully electronic securities quotation system. Market makers could electronically update and view bid and ask quotations in securities traded outside traditional exchange floors. Nasdaq’s account of its first fifty years describes the development of the system.
Early Nasdaq should not be confused with today’s automated order books. Electronic quotations did not immediately mean that every trade was automatically matched by a computer. Dealers still negotiated transactions, including by telephone.
The important change was informational. Quotes that had previously existed largely inside a network of professional dealers could be distributed electronically.
Once market information existed on computers, the next logical step was to automate more of the execution process as well.
Electronic Networks Began Competing With Traditional Trading Floors
During the 1990s, electronic communication networks and other automated systems began playing a larger role in stock execution.
These systems allowed orders to interact electronically rather than depending entirely on traditional floor brokers or dealer negotiations. Nasdaq notes that electronic communication networks became integrated into its market structure during the 1990s, allowing electronic order books to compete alongside established market makers.
The competitive effect was substantial. Markets increasingly competed on speed, fees, available liquidity and technology. Physical trading floors no longer possessed an automatic advantage simply because they were where trading historically occurred.
This also changed professional trading. Floor trading had rewarded physical presence, relationships and an ability to interpret activity in a crowded room. Electronic markets rewarded access to data, software, quantitative models and increasingly fast network connections.
Stock trading was moving from architecture made of stone and people toward architecture made of software and communication links.
The exchange building remained important as an institution. The actual matching of buyers and sellers increasingly happened elsewhere.
The Internet Brought Electronic Stock Trading to Households
Electronic markets existed before ordinary investors could trade through a web browser. The internet connected those systems to retail customers.
The SEC says some customers were already submitting securities transactions through direct dial computer systems during the 1980s, but internet based brokerage systems began appearing in the mid 1990s. Adoption then accelerated quickly.
According to an SEC study, the United States had approximately 3.7 million online brokerage accounts in 1997. That figure reached roughly 9.7 million by the second quarter of 1999. Daily online trading volume increased from fewer than 100,000 transactions in the second quarter of 1996 to more than 500,000 three years later. The SEC’s Online Brokerage: Keeping Apace of Cyberspace documented the rapid change.
The customer’s relationship with the broker changed with it.
An investor who previously called a representative could now type the ticker, quantity and order type personally. Brokerage software replaced much of the conversation.
The broker did not disappear. Its work became less visible.
Online Trading Did Not Mean Direct Access to the Exchange
The apparent simplicity of online stock trading can create a misleading impression. Clicking “buy” does not normally mean the customer’s computer communicates directly with the New York Stock Exchange.
The broker receives the order and determines where it should be routed. Depending on the security and order type, execution might occur on an exchange, through a market maker or through another trading venue.
This distinction matters because execution quality became a major part of modern brokerage economics. Brokers could compete on commissions while using different routing arrangements behind the interface.
Electronic markets also became fragmented. A share listed on one exchange might trade through several competing venues. The investor saw one ticker symbol, while the infrastructure underneath involved exchanges, alternative systems, dealers, clearing firms and consolidated market data.
The modern stock trade therefore became operationally more complicated at the same time that it became easier for the customer.
That paradox remains. Better software can make a complicated market feel almost frictionless without removing the institutions performing the transaction.
The Dot Com Boom Accelerated Retail Stock Trading
The late 1990s combined an important technological change with a speculative market boom.
Internet companies captured investor attention, technology shares produced dramatic price movements and online brokers made frequent trading substantially easier. The result was a rapid expansion of retail participation.
The SEC reported that online trades represented 37% of retail trades during the first half of 1999, compared with 30% a year earlier. Approximately 18% of US investors were trading online by 1999, roughly double the previous year’s figure cited in the same SEC material.
Lower commissions made active stock trading economically possible for smaller accounts in a way that would have been difficult under older brokerage models. An investor could place several trades without paying a large percentage of capital to a human broker each time.
This also exposed the behavioural downside of easier trading. Removing friction makes sensible transactions cheaper, but it makes poor transactions easier too.
When the dot com bubble collapsed, many newly active investors learned that better trading technology did not alter the underlying relationship between valuation, speculation and risk.
Decimal Pricing Changed the Economics of a Stock Trade
American stocks were historically quoted in fractions of a dollar rather than decimals. Prices could move in increments such as one eighth or one sixteenth of a dollar.
The transition to dollars and cents was completed across US equity markets on April 9, 2001. The SEC expected the change to make prices easier to interpret and allow competition at narrower price increments. SEC testimony on decimalisation reported substantial early reductions in spreads.
According to the SEC’s early analysis, quoted spreads on NYSE stocks narrowed by an average of approximately 37% between December 2000 and March 2001, while Nasdaq quoted spreads fell roughly 50% after decimalisation.
The effect may sound technical, but spreads are a real trading cost. A narrower difference between the highest bid and lowest offer can make entering and exiting positions cheaper, particularly for smaller investors.
Electronic trading and decimal pricing therefore reinforced each other by increasing price competition.
Regulation NMS Helped Define the Electronic US Stock Market
As markets became increasingly electronic and fragmented, US regulation had to account for orders moving between competing trading venues.
The SEC adopted Regulation NMS in 2005. The package addressed order protection, access to quotations, market data and restrictions on subpenny quoting. Its Order Protection Rule required trading centres to establish procedures intended to prevent transactions at prices inferior to protected quotations displayed elsewhere, subject to the regulation’s exceptions. SEC Regulation NMS remains an important part of the structure governing American equities.
This period marks the point where the stock market becomes difficult to describe using the old picture of one company listed on one exchange where buyers and sellers meet physically.
Modern equities trade across interconnected electronic venues. Orders can move rapidly between them, and market data systems attempt to make those competing prices visible.
For retail investors the experience became easier. For market engineers it became considerably more complicated.
Stock Trading Moved From Desktop Computers to Phones
The next change was less about market infrastructure than customer behaviour.
Online brokerage initially assumed the investor would sit at a desktop computer. Smartphones removed that constraint. Brokerage apps made it possible to open an account, fund it, analyse a share and enter an order through the same device carried throughout the day.
This reduced trading friction even further. Investors no longer needed to be at an office, branch, telephone or computer terminal. A market alert could produce an order within seconds.
The change also affected how brokers competed. Interface design, push notifications, charts and ease of use became part of the brokerage product. Trading could be presented to new investors without much of the terminology associated with older brokerage services.
That accessibility helped expand participation but also raised questions about whether simplified interfaces can make financial risk appear simpler than it is.
The mechanics of purchasing a share had become easier than at any point in market history. Assessing whether the share was worth purchasing remained just as difficult.
Commission Free Trading Changed What Customers Saw as the Price
The progression from fixed commissions to discount brokerage eventually reached another milestone: zero explicit commissions on many ordinary US stock trades.
Robinhood was an early promoter of the mobile commission free model, and larger US brokerage firms subsequently eliminated commissions on many online equity transactions.
Zero commission did not mean that brokerage businesses stopped earning revenue from trading. One revenue source became payment for order flow, under which trading firms pay brokers for routing customer orders to them.
The SEC’s 2020 enforcement action against Robinhood provides an important example of why the distinction matters. The regulator alleged that between 2015 and late 2018 the broker made misleading statements regarding its receipt of payment for order flow and failed to provide sufficiently good execution for customers in certain circumstances. Robinhood settled the charges without admitting or denying the SEC’s findings. SEC’s Robinhood announcement explains the regulator’s findings.
The historical shift is important: the visible commission fell toward zero, while investors increasingly needed to understand less visible aspects of order execution.
Fractional Shares Reduced the Capital Needed to Start
For most of stock market history, investors purchased whole shares. A high share price could therefore create a practical barrier for a small account.
Fractional share trading changed that. A broker can allow a customer to purchase a dollar amount representing less than one full share. A $1,000 stock no longer necessarily requires $1,000 of available capital.
FINRA notes that fractional ownership existed previously through mechanisms such as dividend reinvestment plans but has become considerably more common as brokerage firms introduced fractional investing for individual customers. FINRA’s fractional shares guidance explains both their accessibility benefits and restrictions that can differ between brokers.
This continued a four-century reduction in the practical barriers to stock ownership.
Early joint stock companies made large enterprises divisible. Exchanges made those ownership claims tradable. Discount brokers reduced transaction charges. Internet platforms reduced operational friction. Fractional shares divided ownership again, allowing investors to purchase smaller economic units than one conventional share.
The stock itself had not become less valuable. The minimum practical purchase had become smaller.
Modern Retail Investors Have More Access and More Choices
Today’s investor can access domestic and overseas stocks, ETFs, fractional shares and derivatives through platforms that would have seemed extraordinary to earlier generations of brokers.
This abundance makes broker selection an important part of stock trading. Investors now compare market access, dealing costs, currency conversion charges, custody arrangements, apps and regulatory status rather than simply using the local brokerage office.
UK investors researching stock access can use resources such as Investing.co.uk as a secondary source for current information on investing, stock trading and brokerage platforms. Its current material includes coverage of both London Stock Exchange brokers and New York Stock Exchange brokers. Regulatory status and investor protection should still be checked through the relevant regulator and the broker’s own legal documentation.
The contrast with early stock markets is striking. Finding a broker was once necessary because the public lacked access. Modern investors face almost the reverse problem: deciding which of many competing platforms should receive their money.
Professional Stock Trading Became Increasingly Automated
Retail investors were moving from telephones to apps while professional trading was undergoing another transformation.
Electronic order books meant prices and orders could be processed by computers. This allowed algorithms to submit, change and cancel orders automatically according to programmed instructions.
Algorithmic trading can be simple. An institutional investor might divide a large transaction into many smaller orders to reduce market impact. More sophisticated firms can process market data and update quotations extremely rapidly.
The result is a market in which a retail investor pressing buy may interact indirectly with algorithms operating far faster than any human trader can react manually.
This does not make fundamental investing obsolete. A pension fund can still decide to own a company because of its expected economic performance over decades. What changed is the machinery executing the transaction.
Stock markets evolved from groups of merchants meeting personally to globally connected networks where much of the moment to moment interaction occurs between computers.
The ownership claim remains human. Much of the transaction process no longer needs to be.
The Physical Exchange Did Not Entirely Disappear
The rise of electronics did not eliminate every trading floor.
The NYSE still maintains a physical floor alongside its electronic market, while many other exchanges became overwhelmingly or entirely electronic. London’s traditional floor disappeared during the Big Bang transition, and the LSE notes that its visitor gallery became redundant when computer and telephone based trading replaced open outcry in 1986.
The survival of the NYSE floor demonstrates that market history does not always progress by completely deleting the previous system. Older structures can remain where participants believe they still contribute to price discovery or auction processes.
Yet the balance of importance has shifted decisively. The physical building is no longer what allows an exchange to reach investors around the country. Network connections do that.
An exchange has become partly a technology company, data provider and regulatory organisation as well as a venue for buying and selling securities.
That would have been difficult to imagine when brokers gathered under the Buttonwood tree.
Trading Became Easier Without Making Investing Easier
The long history of stock trading contains a recurring pattern. Technology repeatedly reduces the effort required to complete a transaction.
The coffee house improved access to information. Formal exchanges organised counterparties. Telegraphs accelerated communication. Tickertape distributed prices. Telephones allowed remote orders. Competitive commissions reduced transaction charges. Computers created electronic markets. The internet let customers enter their own orders. Smartphones made those markets portable, while fractional shares reduced minimum purchase sizes.
None of these inventions solved the investor’s central analytical problem.
The investor still needs to decide what a company is worth, whether expectations embedded in its price are reasonable and how much capital should be exposed to the position.
In some ways lower friction makes those questions more important. Expensive commissions once discouraged constant trading. Modern investors can buy and sell repeatedly with little visible cost. The technical barrier fell, but the possibility of making a poor financial decision did not.
The history of stock trading is therefore partly a history of access, not a history of markets becoming easy to beat.
From VOC Shares to a Trading App
The journey from the Amsterdam exchange to a modern brokerage app spans more than four centuries, yet several pieces of the original system are still visible.
Companies divide ownership into shares because equity capital can finance businesses without requiring scheduled repayment like ordinary debt. Investors buy those shares because they expect economic value from ownership. Secondary markets allow ownership to move between investors without forcing the company to return the original capital.
Everything built around that relationship has become faster.
London brokers progressed from coffee houses to a formal exchange. New York brokers organised through the Buttonwood Agreement. Telegraphs and tickers distributed prices across greater distances. Federal securities regulation formalised oversight after the 1929 crash. Competitive commissions changed brokerage economics after 1975. Nasdaq put quotations on computers, London’s Big Bang accelerated electronic trading, and the internet connected retail customers directly to brokerage software.
By the late 1990s, millions of households were trading stocks online. Decimalisation narrowed quoting increments. Electronic venues competed for orders. Mobile brokers later removed explicit commissions from many transactions, while fractional shares allowed very small accounts to purchase portions of expensive stocks.
A trader in 1602 and an investor using a phone in 2026 would barely recognise each other’s market.
They would recognise the transaction.
One person believes the share is worth buying at the offered price. Another is willing to sell it.
The entire history of stock trading has been built around making that disagreement easier, faster and cheaper to turn into a trade.