ETF liquidity explained: Where it comes from and why it matters

• ETF liquidity makes buying and selling shares fast, fair, and cost-efficient, even when markets are volatile.
• Behind the scenes, market makers and authorized participants (APs) help facilitate trades and keep ETF prices accurate.
• The unique ETF creation/redemption process is a structural advantage that helps ensure the supply of ETF shares matches investor demand.

Imagine walking into your favorite bakery. You grab a few snickerdoodle cookies from the display case and pay. Quick and easy, right? But what if you need a hundred cookies? For a lot of bakeries, that’s still no problem—they can quickly whip up fresh batches using their commercial ovens and industrial-grade kitchens.

That’s a short-and-sweet version of how exchange traded fund (ETF) liquidity works.

When you trade ETF shares, most of the time you’re just taking from what’s already “on the shelf.” But when demand spikes, a network of traders and institutions (the unseen bakers in the kitchen) step in to create or redeem shares so there’s always enough supply—and prices stay fair.

A simple explanation for a complex system, but it’s what makes ETFs one of the most flexible and accessible investment options out there. Let’s step behind the counter, put on our aprons, and see how ETFs are baked.

The ETF marketplace: Providing two layers of liquidity

Every ETF operates in two markets. You can think of them as the front counter and the kitchen of our figurative bakery.

1. The secondary market (the front counter). This is where most trading happens. Investors buy and sell existing ETF shares on an exchange, just like stocks.
2. The primary market (the kitchen). Sometimes demand is so high that the “display case” can’t satisfy everyone’s appetite. When that happens, large institutional players called authorized participants (APs) step in to create or redeem ETF shares directly with the fund.

Creation: If more shares are needed, APs buy the underlying securities (the ingredients, if you will), deliver them to the fund company, and receive newly minted ETF shares in return.

Redemption: While you can’t unbake a cookie (thank goodness), you can unwrap an ETF. If demand fades, APs do the reverse—returning ETF shares to the fund in exchange for the underlying holdings.

This two-layer structure is what gives ETFs their hallmark liquidity. Whether you’re buying a handful of shares or placing a much larger order, there’s usually someone on the other side ready to trade and a “baker” in the kitchen making sure the shelves stay stocked.

How do ETFs trade? The role of market makers and APs

ETF trading is supported by a network of market participants working behind the scenes to keep prices fair and trading efficient. Two of the most important are market makers and APs.

Market makers quote real-time bid (buy) and ask (sell) prices on the exchange. The small gap between the two (known as the bid-ask spread) is essentially their paycheck for facilitating trades. And since multiple market makers compete to fulfill orders, they’re motivated to keep that spread tight. That helps lower trading costs for investors, even during busy or volatile markets.

Of course, sometimes demand exceeds or falls short of what’s available “on the shelf.” To address this, APs step in behind the scenes to create or redeem ETF shares as needed, keeping supply and demand in balance.

This ongoing process—market makers facilitating trades and APs adjusting supply—creates a self-correcting system. When ETF shares trade above the value of their holdings (a premium), APs can create more shares to bring prices back down. When shares dip below (a discount), they redeem shares to push prices back up.

That constant balancing act is what makes ETFs so efficient.

Additional ETF liquidity players: Exchanges, short sellers, and more

Market makers and APs might be the head bakers of the ETF liquidity story, but they’re not working alone. Behind them is a full kitchen team, each playing a specific role to keep everything running smoothly. You’ll probably never interact directly with any of them, but their collective effort means you can buy or sell an ETF in seconds, at a fair price.

Exchanges
You can’t spell exchange traded fund without exchange. And as their name proudly states, ETFs trade on exchanges like the NYSE or Nasdaq. What you might not know is there are other trading venues, like electronic communication networks and over-the-counter markets. These are used mainly by institutions, so they aren’t very relevant to retail investors, but they do help maintain price stability.

Broker-dealers
There are brokers, dealers, and even broker-dealers. Brokers act as your agent, routing buy and sell orders to the best possible venue. Dealers buy and sell securities for their own account. They charge commissions for their services to execute and settle trades. And broker-dealers, as you might suspect, do both.

Derivative trading desks
When institutions trade futures, options, or swaps tied to an ETF, derivative desks often step in to hedge their exposure by buying or selling the ETF itself. Those hedging trades help add liquidity to the market.

Short sellers
Short sellers gained a relatively notorious reputation during meme stock mania, but they serve an important role. They tend to sell when prices rise (adding supply) and buy when prices fall (adding demand), helping increase overall market liquidity.

ETF issuers
An ETF issuer develops ETF products, determines fund investment objectives, and manages ETF portfolios accordingly. Its capital markets team maintains relationships with APs, market makers, and exchanges to keep spreads tight and trading efficient. Its portfolio managers ensure the underlying holdings are liquid enough to support daily trading.

Why understanding ETF liquidity matters

You’ll probably never meet an authorized participant or chat with a market maker over coffee—and that’s fine. You don’t need to. What matters as an investor is knowing why ETF liquidity makes your life easier.

Fast and fair trades. Lower costs. Access to harder-to-reach markets.

Liquidity might not be something you think about every day, but like cream of tartar in snickerdoodles, it’s the secret ingredient that makes ETFs work.