Cboe BYX: The Inverted Equities Exchange

Key Takeaways

• Cboe BYX is an inverted equities exchange, the opposite of the standard maker-taker model.
• It charges traders who add liquidity and pays a rebate to traders who remove it.
• The inverted model rewards speed, giving takers a reason to fill aggressively.
• BYX has hosted Periodic Auctions, short price-forming auctions held during the trading day.

What It Is

Cboe BYX is a registered national securities exchange for U.S. stocks. It started as a BATS venue and became part of Cboe when the company acquired Bats Global Markets in 2017. It sits next to three sister markets: BZX, EDGX, and EDGA.

The defining feature of BYX is its inverted fee model, sometimes called taker-maker. On a normal exchange the trader who posts a resting order earns a rebate and the trader who removes it pays a fee. BYX reverses both sides.

The Intuition

Inverted pricing exists to attract a specific kind of order flow. By paying the taker a rebate, BYX gives traders who need an immediate fill a reason to route there first. A broker whose client wants speed, or who passes exchange fees straight through, finds an inverted venue economical because removing liquidity earns money instead of costing it.

The flip side is that posting on BYX costs a fee rather than earning a rebate. That fee is what funds the taker rebate. The model competes for a different slice of the market than maker-taker venues, which is why a fragmented market can support both kinds at once.

How Cboe BYX Works

On BYX, a trader who posts a resting limit order is the maker and pays a fee when it fills. A trader who sends a marketable order that executes against the book is the taker and earns a rebate. The structure is a mirror image of a maker-taker exchange:

Maker-taker venue:  add = rebate, remove = fee
Inverted venue:     add = fee,    remove = rebate

BYX still matches on price-time priority and must honor the national best bid and offer like every U.S. exchange. The inverted economics mainly change where smart-order routers send aggressive orders. Routers that want to capture the take rebate or fill quickly often check inverted books early in their sweep. BYX has also offered Periodic Auctions, brief auctions during the day that gather interest and cross it at a single price, giving traders a way to source liquidity without continuously displaying a quote.

Worked Example

Suppose a stock is quoted 40.10 bid, 40.12 offer, with shares resting at both prices on BYX. You need to buy 1,000 shares right now and route a marketable order to BYX.

Your order removes liquidity by lifting the 40.12 offer. Because BYX is inverted, you, the taker, earn a small rebate on those 1,000 shares instead of paying a fee. The trader who had posted the resting offer is the maker and pays the exchange's add fee.

On a maker-taker venue the cash flows would be reversed: you would pay to take, and the resting seller would earn the rebate. Same trade, opposite economics, which is the whole point of routing to an inverted book when speed or take-side cost matters most.

Common Mistakes

1. Assuming all exchanges pay you to post. On BYX the maker pays and the taker is paid. Posting a resting order there can cost a fee rather than earn a rebate.

2. Confusing BYX with BZX. They share a parent and a matching engine style but run opposite fee models. BZX is maker-taker; BYX is inverted.

3. Overrating market share. Inverted venues are a niche of total volume, and that share has shifted over time. BYX is one competitor among many, not a dominant venue.

4. Ignoring why a router chose it. If your order filled fast on an inverted venue, the take rebate may be part of the reason. The execution quality still depends on the national best bid and offer.

5. Treating the rebate as free money. The taker rebate is small and exists to attract flow. It does not change the underlying price you pay, only the fee layer on top.

Frequently Asked Questions

What is Cboe BYX in simple terms? Cboe BYX is a U.S. stock exchange that uses an inverted fee model. It charges traders who post resting orders and pays a small rebate to traders who take liquidity, the reverse of most exchanges.

How does Cboe BYX affect investment decisions? For most individual investors it is invisible, since a broker decides where to route. For active traders, BYX can lower the cost of aggressive orders because removing liquidity earns a rebate rather than paying a fee.

What is a real-world example of Cboe BYX in action? A broker with a client who wants an immediate fill routes the marketable order to an inverted venue like BYX, captures the take rebate, and offsets part of the trading cost.

How can investors use Cboe BYX effectively? If you trade actively and your broker exposes routing, sending marketable orders to an inverted venue can earn a take rebate, while resting orders may be cheaper on a maker-taker venue instead.

How is Cboe BYX different from Cboe BZX? BZX is maker-taker: it pays the maker and charges the taker. BYX is inverted: it charges the maker and pays the taker, which appeals to traders who value speed and take-side economics.

Sources

1. Cboe. "BYX U.S. Equities Exchange Fee Schedule." https://www.cboe.com/us/equities/membership/fee_schedule/byx/
2. Cboe Insights. "The Value of Inverted Exchanges." https://www.cboe.com/insights/posts/the-value-of-inverted-exchanges/
3. Cboe. "U.S. Equities Exchanges Overview." https://www.cboe.com/us/equities/
4. Cboe. "Order Types and Routing." https://www.cboe.com/us/equities/trading/offerings/order_types_and_routing/

Disclaimer

This article is educational content only and is not financial advice. Nothing here is a recommendation to buy, sell, or hold any security. Consult a licensed advisor before making investment decisions.