The 2026 Intern’s Information to the Market Construction Galaxy

IT’s that point of 12 months once more when many people have interns becoming a member of the desk. So, over the subsequent few weeks, we’ll replace our guides on buying and selling, exchange-traded funds (ETFs) and choices. 

As all the time, we’ll embrace hyperlinks to extra analysis for interns seeking to take a deeper dive into any of the matters talked about.

If you’ve labored out there for years, we all know all of this. Simply benefit from the refresher — you by no means know when an intern would possibly ask a query in regards to the fundamentals.

Markets assist match patrons and sellers in an environment friendly means

All markets, even those the place you store for groceries, have a reasonably easy underlying goal: to deliver collectively patrons and sellers. Doing commerce in a centralized means permits shoppers to match costs and producers to promote to extra clients directly. Economically, IT’s a win-win.

Inventory markets add one other dimension as in addition they present firms with entry to traders. Money from traders permits firms to put money into their companies, improve hiring and increase the financial system. As well as, that financing helps firms develop earnings, which, in flip, offers earnings again to the traders.

The markets are an ecosystem

Whether or not centralized or not, markets work finest with a various ecosystem of members, every with their very own specialised function to play in shopping for, promoting and valuing shares.

Traders present capital to firms, which then present dividends and returns to traders. Banks assist traders worth shares, whereas exchanges permit merchants to offer liquidity and arbitrageurs to right mispricings. This all occurs at the identical costs regardless of the completely different commerce alerts and lengths of time they maintain shares. 

Totally different targets and time horizons matter. For instance, an arbitrageur would possibly see ETFs dislocate from inventory values for a couple of seconds, however a mutual fund portfolio supervisor could resolve to purchase a inventory to carry for 2 years based mostly on anticipated progress in gross sales.

Chart 1: The inventory market ecosystem

Itemizing exchanges deliver all members collectively

Itemizing exchanges play a central function in inventory markets, actually. They checklist firms, assist merchants purchase and promote their shares, and share costs with different traders and analysts.

Itemizing exchanges even have itemizing requirements, which work alongside the U.S. Securities and Change Fee’s (SEC) guidelines that require corporates to share quarterly accounting statements (for now) and different disclosures. That makes inventory markets extra clear and comparatively safer for traders. That’s why pension and mutual funds usually solely make investments in so-called “listed” shares.

There are round 5,500 firms and over 5,000 ETFs which are traded within the U.S. 

The place a inventory is “listed” impacts what “tape” its costs and trades are reported on. There are historic causes for that. Up to now, trades have been actually printed onto paper “ticker tape” from the situation the place trades have been taking place. At this time, there are nonetheless three “tapes” that publish trades and costs:

• Tape A is for all NYSE listings (no matter what trade the commerce truly happens on).
• Tape C is for all Nasdaq listings (no matter the place trades happen).
• Tape B is for all different exchanges, together with the Cboe exchanges and NYSE Arca (which predominantly checklist ETFs) in addition to NYSE American (which generally lists small firms).

Chart 2: Variety of U.S. firms on every “tape”

Index suppliers use the major itemizing trade’s closing public sale to calculate the final “official” commerce of the day. That makes the closing public sale for the first trade essential for matching liquidity and minimizing volatility. IT‘s additionally essential for mutual funds that use the shut to calculate unit costs which are used to make investments buyer money flows.

Though only some exchanges checklist shares, all exchanges can commerce shares, and all are required to be open to everybody. One other factor that each one exchanges do is to promote costs to everybody. 

Public costs assist patrons discover sellers and commerce at the perfect costs out there. Additionally they assist non-traders worth portfolios and let portfolio managers purchase dips and promote peaks. Competitors for the perfect costs additionally creates tighter spreads that scale back transaction prices for all traders (even those that don’t commerce on an trade).

That offers what economists name “optimistic externalities.” Everybody advantages – even those that aren’t buying and selling. 

Issuers give us tickers to commerce and dividends to avoid wasting

Corporations, additionally known as “issuers” as a result of they problem shares, are essential to public markets and to the U.S. financial system. With out issuers becoming a member of public markets, there would be no public firms to put money into, no dividends for traders, and fewer methods to hedge and commerce.

Traders then profit from dividends and capital good points, that are generated primarily by earnings progress.

Chart 3: Within the long-run, inventory costs align carefully with earnings

The day of an preliminary public providing (IPO) is essential for an organization, too. Elevating money can permit an organization to develop. Having a inventory that trades additionally makes IT simpler to problem extra shares (in a “secondary” elevating) sooner or later. That makes IT simpler to put money into gear and staff – rising revenues and the financial system.

Apparently, IPO exercise rises and falls based mostly on a number of financial components. IPOs additionally signify a possibility for traders to learn from the liquidity premium that public buying and selling provides to a inventory, which additionally occurs beforehand. On common, day-one returns for IPOs are optimistic.

Importantly, U.S. inventory markets aren’t the one place new firms can discover traders. Our listed markets compete with personal markets, OTC markets (previously together with pink-sheet and bulletin board shares) and worldwide inventory markets for listings.

That stated, the U.S. inventory market is engaging to issuers. IT has the most important supply of fairness capital, stronger valuations, the lowest buying and selling prices and, arguably, the most liquidity on this planet.

Issuers want traders

With a purpose to increase capital, issuers want to draw traders. Lengthy-term traders are available two principal flavors: 

• Mutual funds and pension funds (additionally known as “institutional traders”) are the place an expert manages a portfolio for a gaggle of particular person traders.
• Retail traders (or “households” in Chart 4) can execute trades and handle their very own portfolios instantly from an app on their telephones, or typically with the assistance of a monetary advisor.

Information suggests they each have roughly the identical quantity of capital to take a position (roughly $20 trillion every).

Chart 4: Who owns shares (based mostly on year-end 2025 knowledge) 

All traders are attempting to maximise their funding returns. Many mutual funds will analysis shares to attempt to discover firms that can develop revenues the quickest, pay the perfect dividends, have the perfect revenue margins, or supply the perfect worth (nonetheless you outline that). 

These funds and the professionals managing them present an essential function in what we name “value discovery.” Their shopping for makes good firms’ costs go up, whereas firms with much less rosy outlooks see their costs fall as traders promote. IT is a part of what helps markets effectively allocate capital. Nonetheless, actively choosing shares that outperform can be how portfolio managers attempt to beat the market.

Different portfolio managers run index funds. These attempt to purchase each inventory in an index, normally at market weight. These funds save prices, as they do much less analysis and far much less buying and selling. They’re additionally relying available on the market’s general effectivity to make sure the costs they pay should not too excessive (for buys) or too low (for sells). 

Information evaluating returns of index and lively funds suggests the market could be very environment friendly. Current knowledge additionally exhibits that the assets in index funds are actually bigger than these in actively managed mutual funds.

Chart 5: Index vs. lively mutual funds as a p.c of all shares 

Retail traders additionally need to maximize funding returns, or at the very least reduce losses. As app-based buying and selling and commission-free buying and selling has made IT simpler for retail to commerce than ever earlier than, retail buying and selling has remained comparatively strong regardless of latest geopolitical uncertainty. One factor the information additionally exhibits is that though retail commerce shares extra, they are constantly internet patrons of ETFs, a type of mutual fund that trades on trade.

Issuers and traders want banks and brokers

More often than not, issuers and traders want banks and brokers to assist them enter and exit the market. 

Banks have many direct relationships with issuers and mutual funds. They usually lend to firms. Additionally they analysis firms and execute trades for mutual funds, typically utilizing their very own various buying and selling techniques (ATSs), resembling darkish swimming pools. So, they contribute to each capital formation and liquidity.

Forward of an IPO, brokers will canvass traders to evaluate curiosity, assist value and allocate shares within the IPO. The IPO is named a major market. 

Then, as traders purchase and promote shares to vary their portfolio holdings in so-called “secondary” markets, they normally want brokers to “work” their orders over time.

Traders want shorter-term merchants to maintain markets environment friendly

There may be not all the time one other investor seeking to promote when a brand new investor needs to purchase. That’s the place short-term merchants – from hedge funds and banks to market makers and arbitrageurs – assist. 

Though every has completely different funding targets, all of them play a essential function in conserving markets environment friendly and liquidity low-cost. Our estimates additionally recommend they make up the majority of buying and selling (Chart 6).

Chart 6: Traders have nearly all of property; intermediaries do nearly all of buying and selling

Market makers don’t maintain shares for lengthy, however their specialty is being each a purchaser and vendor on the identical time. Making a “two-sided market” in every inventory ensures traders can commerce no matter whether or not they wish to purchase or promote. In return, market makers hope to earn the unfold, or the distinction between the bid and the supply.

Arbitrageurs assist futures and choices monitor their underlying asset costs very effectively. Our analysis exhibits that ETFs commerce in line with their portfolios’ internet asset values even when the ETF doesn’t commerce. Thanks to classy statistical hedging methods, many ETFs are literally cheaper to commerce than their underlying shares.

Hedge funds, in distinction, have a tendency to carry lengthy and quick positions on the identical time. Their methods usually hold related shares, typically known as pairs, effectively valued. That helps hold markets extra environment friendly, including promoting to a purchaser of 1 inventory by shopping for a hedge from a vendor of one other inventory. Analysis even exhibits that quick sellers assist hold markets environment friendly by including sellers to overbought shares.

Market guidelines have advanced over time

Inventory markets have rallied and crashed a number of instances in historical past. Usually, following bear markets, guidelines are modified to guard traders. That’s precisely what occurred after the most important bear market in U.S. historical past, which adopted the Nice Despair within the U.S., the place shares fell over 85% from their highs as unemployment reached 24.9%.

Chart 7: Market rises and falls (log scale)

Defending traders from unscrupulous intermediaries

For instance, in the last decade that adopted the Nice Despair, U.S. markets noticed the introduction of numerous new guidelines to guard traders:

• Securities Act of 1933: Established guidelines for IPOs in order that traders would have Information on which to base their funding valuations.
• Banking Act of 1933 (often known as the Glass-Steagall Act): Separated business banks that lent homebuyers cash and funding banking that traded shares and bonds. To this present day, insurance coverage on financial institution accounts (FDIC) and brokerage accounts (SIPC) is completely different, though Glass-Steagall was repealed, permitting at this time’s mega-banks to do inventory broking and banking for his or her clients.
• Change Act of 1934: Established the SEC to control inventory and choices markets, and set exchanges as self-regulatory our bodies (SROs) liable for policing their very own listed firms and buying and selling guidelines.
• Formation of NASD in 1938: The Nationwide Affiliation of Securities Sellers (NASD) regulated the buying and selling of shares that weren’t listed on exchanges. IT has since turn out to be Nasdaq (buying and selling) and FINRA (dealer regulation).
• Funding Firm Act of 1940: Set all the principles that mutual funds (together with ETFs) must comply with, together with protected custody of property and limits on leverage.

Competitors for buying and selling and the fragmentation of liquidity

One other important regulatory change occurred in 1975 with the Securities Act Amendments. These guidelines arrange what we now name the Nationwide Market System (NMS). Maybe most importantly, brokerage fee charges have been deregulated by the SEC, a transfer that drew important criticism as Wall Road cried May Day. Nonetheless, in a development that may play out once more over the next many years, decrease prices led to rising quantity that has lengthy since made up for decrease charges.

Then, in 1994, Congress handed the Unlisted Trading Privileges Act of 1994, which allowed any trade to commerce any ticker—no matter the place that inventory was listed. At this time, there are 17 exchanges and greater than two dozen darkish swimming pools, all of which can commerce any listed U.S. inventory. There may be additionally an increase in “off-exchange” buying and selling, which incorporates darkish swimming pools, retail buying and selling, and bilateral buying and selling. This has been growing up to now 12 months as a consequence of segmentation and the curiosity in 24-hour buying and selling.

Though Instinet launched the primary darkish pool in 1986, Reg ATS didn’t set constant guidelines for darkish swimming pools to commerce in till 1999.

Chart 8: At this time’s market is fragmented, with many venues in a position to commerce any shares they need

Market automation additionally began within the ‘70s

IT most likely appears arduous for an intern to consider, however as lately because the Nineteen Nineties, most shares have been traded in particular person, in “pits” or at “posts” on the ground of an trade, with every commerce written down on tiny items of paper that have been taken again to the workplace to be processed for purchasers. The following day, interns would most likely be part of “runners,” delivering bodily inventory certificates from the vendor’s dealer to the client’s dealer.

Some flooring do nonetheless exist at this time, however the U.S. market began to automate again in 1971, an occasion that in the end created Nasdaq. Nasdaq’s first “knowledge facilities” had tape drives, monochrome cathode tube screens, sideburns and plaid trousers – a lot has modified since then.

Exhibit 1: A Nasdaq knowledge middle in 1971, the 12 months the corporate’s digital trade started working

With most floor-based markets, all traders would see was a ticker tape of historic trades, actually a rolled-up piece of paper with typing on IT, effectively after the trades had truly occurred. Even at this time, the business refers informally to the document of all quotes and trades as “the tape.” You would possibly even hear a dealer nonetheless say a commerce has “hit the tape,” which suggests IT is now on the display and within the database.

Shifting from automated quotes to trades

In its first iteration, the Nationwide Affiliation of Securities Sellers (NASD, now FINRA) constructed a system for market makers in OTC (typically micro-cap) shares to electronically replace their bid/ask quotes. That grew to become the NASD Automated Quotations (therefore the acronym NASDAQ).

Exhibit 2: One of many early Bunker-Ramo pc terminals used to make and see quotes

Over time, as computer systems improved, extra knowledge might be shared extra simply. This benefited traders and merchants who couldn’t essentially see what was taking place on different human buying and selling flooring.

The primary knowledge innovation within the Eighties was the creation of a real-time “Degree 2” knowledge feed. Greater than merely offering the perfect bid and supply, Degree 2 confirmed all market maker quotes at completely different costs beneath the bid and above the supply. What’s now known as “depth.”

Exhibit 3: The quote montage from the Nasdaq Workstation II within the late Nineteen Nineties, displaying depth (Notice costs are in fractions of a greenback; some bonds nonetheless commerce in fractions at this time)

Automating executions after the 1987 crash

One other huge market crash occurred in 1987 when the S&P 500 fell greater than 20% in at some point. Again then, there have been no market-wide circuit breakers or different guardrails to gradual markets down and permit patrons time to reassemble.

Within the aftermath, IT was found that many market makers have been unable or unwilling to commerce though purchase costs might be seen on the screens. Shortly after, the method of matching trades was additionally automated, creating what we now name “actionable quotes.” Though of their early types:

1. The Small Order Execution System (SOES) automated executions as much as a most of simply 1,000 shares to guard market makers from massive market actions.
2. The SelectNet system allowed merchants to create locked-in trades — though IT labored much more like electronic mail for buying and selling.

Decrease prices drive liquidity and exercise into the 2000s

Nonetheless, that units the scene for a market that appears extra like what we all know at this time – the place nearly all trades are executed electronically. And because the market adopted computerized buying and selling, essential new guidelines have been launched:

• 1997 – Order Handling (Manning) Guidelines: Now that clients may be part of the identical bid as market-makers, manning required brokers to place buyer orders first. That made IT simpler for traders to commerce with one another and seize extra spreads.
• 2001 – Decimalization led to quotes being in cents, which we see at this time, not fractions, as we noticed within the level-2 display above. Decimals got here shortly after fractional ticks have been diminished from eighths to sixteenths in 1997, all of which made unfold prices a lot smaller and market-making much less worthwhile.
• 2007 – Reg NMS mandated many issues we take as a right at this time: quotes which are publicly accessible and actionable, costs that may be consolidated in real-time to create an NBBO, and an interconnected market that helps traders all the time commerce on markets with the perfect costs.

Because of this, market-making grew to become extra automated, and buying and selling grew to become cheaper. From 1995 to 2005, markets noticed spreads decline 90%, and liquidity elevated tenfold. Apparently, this all occurred earlier than Reg NMS was applied in 2007.

Chart 9: The influence of market-wide automation lower buying and selling prices and boosted liquidity

As a result of spreads are so tight, and trades are all reported electronically now, newer SEC guidelines have been targeted on altering ticks as soon as extra, in addition to including extra knowledge and smaller trades to public feeds.

Buying and selling on the pace of sunshine

This all signifies that over the previous 50 years, buying and selling has gone from human pace to pc pace to the pace of sunshine. Though for any interns working in digital buying and selling, IT is perhaps essential to know that mild travels quicker in air than in optic fiber.

Computerized buying and selling has led to fewer handbook errors, quicker processing and cheaper buying and selling. IT has additionally made buying and selling quicker. Lots quicker. 

In actuality, nearly all buying and selling in U.S. shares is completed in knowledge facilities in New Jersey nowadays. On the pace of sunshine, IT takes trades about 0.0002 seconds, or lower than 0.2 milliseconds (ms), to journey from one trade to a different. To place that in perspective, a human blink takes round 1 / 4 of a second (that’s 250 milliseconds). 

All of this is to say that arbitrage occurs in a short time, and markets are actually very environment friendly.

Chart 10: Distances between buying and selling facilities on the pace of sunshine

The place do public costs come from?

Within the U.S., a collection of centralized computer systems, known as the SIPs, places all of the fragmented quotes again collectively. 

The SIPs obtain the perfect bid and supply from all of the exchanges for each inventory out there. They then type this Information to search out which trade has the perfect bid and which trade has the perfect supply. Then IT creates a single unified nationwide finest bid and supply (NBBO), which is made accessible to all traders. 

These are the “tapes” that we talked about earlier. IT additionally lets traders know what the perfect value is, and the place they should go to get IT.

Chart 11: SIPs compile the NBBO based mostly on all of the exchanges’ quotes in a selected safety

Though the key enchancment in spreads occurred over 20 years in the past (Chart 8), the market infrastructure has continued to evolve to maintain up with the adjustments in computing energy. Up to now 14 years, the SIP has elevated its capability greater than 40-fold whereas on the identical time decreasing the time IT takes to calculate the perfect value by extra than 99.6%.

Chart 12: The SIP has been in a position to deal with extra messages at a quicker fee over time

Market construction helps everybody make investments and commerce higher

At this time’s inventory markets are quick and complex. However the excellent news is that there are many guidelines designed to make IT look easy and defend traders. 

That’s to not say they’re good. There are ongoing debates about issues like spherical tons and tick sizes, retail buying and selling and short-selling guidelines, in addition to competing concepts on the optimum method to allocate the economics of value setting and buying and selling.

General, although, our market construction helps make U.S. markets a number of the least expensive and most liquid to commerce in — and that’s good for traders and issuers.