SEC Targets 20-Year Rule — Could Unlock Tokenized Stock Trading

Big news from the regulatory circus: the Securities and Exchange Commission has proposed tossing out a pair of old rules that have quietly governed how U.S. stock trades behave for roughly two decades. The short version: Rule 611 (the so-called “trade-through” rule) and Rule 610(e) are on the chopping block, and that could make a world of difference for on-chain trading experiments and tokenized stocks — or at least make the conversation much louder.

Why Rule 611 has mattered — and why it bugs automated market makers

Rule 611 was born back in 2005 to stop your orders from being filled at worse prices when a better quote sat on another exchange. It tied trading to the National Best Bid and Offer (NBBO), and traders, brokers, and exchanges built lots of infrastructure around that guarantee. It’s been the plumbing of equities trading ever since.

But blockchains and automated market makers (AMMs) don’t play by the same rules. AMMs price trades via bonding curves, liquidity pools, slippage and block-time batches — not by matching against a centralized, consolidated quote feed. That means an on-chain pool can legitimately produce prices that are different from an NBBO snapshot, and that’s a huge headache when you’re legally required to avoid “trade-throughs.”

Practically speaking, an AMM can’t easily do things that traditional market venues do: route intermarket sweep orders, ingest consolidated market data with millisecond guarantees, or halt a swap the moment a fleeting better quote appears on a major exchange. The result? A pool could appear to be constantly violating the trade-through rule or acting like an unregistered trading center — even when it’s just doing AMM stuff.

Rule 610(e) complicates things further because AMM prices can drift as liquidity shifts and trades slice through pools. That drift can produce locked or crossed prices against the NBBO — a situation current rules try to prevent.

What might change — tokenized stocks, best execution, and market design shakeups

If the SEC goes ahead and rescinds Rule 611 (and 610(e) gets tweaked or removed), the regulatory focus would likely swing toward best execution requirements instead of per-trade NBBO protection. That’s a subtler regulatory framework: brokers would have to show they used reasonable diligence to get good results for customers over time, document routing choices, and compare venues, rather than guaranteeing every single trade matched an NBBO snapshot.

For tokenized stocks — blockchain-based representations of shares or claims on shares — this could be huge. Token fans argue tokenization enables 24/7 trading, fractional ownership, faster settlement, and easier cross-border access. Industry folks say the real barrier has been rules like 611 rather than a lack of technical ability. Pull that barrier down and the whole experiment looks a lot more doable.

But don’t start celebrating a free-for-all just yet. Rescinding Rule 611 wouldn’t instantly legalize tokenized equities or answer crucial questions: Is the token a direct share, a custodial claim, a derivative, or a synthetic product? Who holds the underlying asset? How are dividends and corporate actions handled? Where does the token trade? Who’s responsible for settlement, custody, and investor protections? Lots of boxes still need checking.

There are also broader market-design implications. Rules like 611 have influenced how exchanges display quotes, how liquidity competes, and even what kinds of microstructure experiments (like asymmetric speed bumps) can get off the ground. Removing the rule would change incentives for exchanges and brokers, and that could reshape routing, quoting, and venue competition in ways that help some players and annoy others.

Expect polarized reactions. DeFi and tokenization advocates see a potential unlock for innovation. Traditional market groups and some investor advocates worry about fragmentation, weaker displayed quotes, or harder-to-compare execution quality for ordinary investors. Regulators will get a flood of public comments debating whether this is modernization or market destabilization.

Short version: the proposal is an important step toward making blockchain-friendly trading architecture more feasible, but it’s not a magic wand. The SEC may follow with targeted exemptions, temporary frameworks, or additional rulemaking to handle exchange registration, custody, and settlement issues. For now, the industry gets a permission slip to argue and experiment — and the rest of us get front-row seats to the rules-of-the-road rematch.

Bottom line: this could be the beginning of a real regulatory pivot toward tokenized markets, or it could be a long, slow rewrite with lots of guardrails. Either way, people building on-chain trading systems and the regulators watching them are about to have a very busy comment period.