Nasdaq filed new rules describing how it will halt and reopen exchange-traded products during planned 23/5 trading. The Securities and Exchange Commission published the immediately effective filing on October 13, adding operational safeguards before Nasdaq expands trading across 23 hours each weekday.

Nasdaq 23/5 trading adds halt procedures

The SEC listed filing SR-NASDAQ-2026-088 as immediately effective on October 13. Nasdaq amended Equity 4, Rule 4120 to specify when exchange-traded products must stop trading and how they can reopen during 23/5 operations.

Exchange-traded products include funds and other securities whose market value may depend on an index, commodity, currency or underlying portfolio. Overnight trading creates added complexity because some reference markets may be closed or key values may not be calculated continuously.

The rule framework gives Nasdaq a process for pausing products when required information is unavailable or when the primary listing market halts the security. A halt can prevent trades from continuing when participants lack the data needed to form reliable prices.

Why Nasdaq 23/5 trading raises liquidity risks

Longer hours increase access, but they do not guarantee the liquidity available during the regular session. Fewer competing orders can widen bid-ask spreads, increase price gaps and make market orders more expensive to execute.

Overnight prices may react to news before the underlying assets or related derivatives reopen. That can make an exchange-traded product’s displayed price less informative and leave market makers with higher hedging costs.

The risk differs by product. Broad equity funds may have more reference prices and competing liquidity than niche commodity, currency or international funds whose underlying markets follow different operating hours.

Those risks can be greater for specialized or lightly traded funds. Investors may also see an exchange-traded product move away from its indicative or underlying value when the reference assets are not trading at the same time.

Nasdaq’s filing concerns market operations rather than approval of a new fund. It also does not promise that every listed exchange-traded product will trade continuously throughout the full 23-hour window.

What investors should check before overnight trades

Investors should review order types, spreads and available depth before placing an overnight trade. Limit orders can control the maximum purchase price or minimum sale price, although they do not guarantee execution.

Our bid-ask spread guide explains how thin order books affect trading costs. Readers can also review ETF creation and redemption mechanics and the federal funds rate for related market-structure context.

The SEC notice opens a public-comment period tied to Federal Register publication. Market participants will now focus on Nasdaq’s implementation timing, eligible products and coordination with primary listing markets before 23/5 trading begins.

Featured image: Nasdaq market information screen. Photo by Daniel via Unsplash.

Elsy Kanana is a financial and cryptocurrency journalist at FusionMarketNews, covering digital assets, blockchain technology, financial markets, and emerging fintech trends. Her reporting focuses on market movements, regulatory developments, and on-chain analytics, delivering clear, data-driven insights to readers worldwide.