A security token offering (STO) is a sale of securities, such as equity, debt or fund units, where ownership is recorded and transferred as blockchain tokens. Unlike most ICOs of 2017, an STO accepts from the start that securities law applies, and builds investor checks and transfer restrictions into the token.
STO, ICO, IEO: the difference
ICOs sold tokens to anyone, usually claiming they were utilities rather than investments. Regulators disagreed in many cases, and US enforcement through the late 2010s established that tokens sold with an expectation of profit from a team's efforts can be investment contracts under the Howey test. Exchange-hosted IEOs moved the sale onto a centralized venue but did not change the legal analysis. STOs start from the opposite assumption: the token is a security, so the offering uses a securities route. For comparison, see ICO development and IEO services.
The main legal routes
United States
| Route | Who can invest | Raise limit | Notes |
|---|---|---|---|
| Reg D 506(b) | Accredited investors (plus up to 35 sophisticated non-accredited) | None | No general solicitation; Form D filing |
| Reg D 506(c) | Accredited only, verified | None | General solicitation allowed |
| Reg S | Non-US persons, offshore | None | No directed selling efforts into the US |
| Reg A+ Tier 2 | Anyone (non-accredited subject to investment limits unless listed) | $75M per 12 months | SEC-qualified offering circular, ongoing reports |
| Reg CF | Anyone, with per-investor limits | $5M per 12 months | Must use a registered funding portal or broker-dealer |
Securities sold under Reg D are restricted: resale generally waits for Rule 144 conditions, and trading after that usually happens through a broker-dealer or an alternative trading system (ATS). The SEC's posture toward crypto shifted noticeably in 2025, with a new chair, dropped enforcement cases and a stated program to modernize rules for tokenized securities. The underlying securities laws have not changed, so plan around them and track the SEC's current guidance.
European Union
MiCA, which applies to crypto-asset service providers from December 2024, explicitly excludes tokens that qualify as financial instruments. Security tokens therefore fall under MiFID II, the Prospectus Regulation and related rules, as with any transferable security. The DLT Pilot Regime, applying since March 2023, lets authorized market infrastructures operate DLT-based trading and settlement systems under specific exemptions. A few member states, notably Germany, have laws for electronic securities that can be issued on a crypto ledger.
Elsewhere
Switzerland's DLT Act recognizes ledger-based securities directly. Singapore treats most security tokens as capital markets products under the Securities and Futures Act. The UK regulates them as specified investments under FSMA, and runs a Digital Securities Sandbox for market infrastructure. Each country page in our regional guide covers local regulators.
The lifecycle of an STO
- Structuring: issuer entity, instrument terms, offering route, target investors and countries.
- Documentation: private placement memorandum or offering circular, subscription agreement, token terms describing on-chain controls.
- Technology: permissioned token (ERC-3643 or ERC-1400 family), identity registry, investor portal, audited contracts. The tokenization platform guide details the stack.
- Service providers: transfer agent or registrar, custodian, KYC provider, placement agent or broker-dealer where needed.
- Marketing within the rules of the chosen exemption; see STO marketing.
- Subscription and issuance: KYC and eligibility, payment, minting to verified wallets, regulatory filings.
- Post-issuance: investor reporting, distributions, corporate actions, transfer approvals, and secondary trading through a licensed venue.
Lessons from the first STO wave
- Liquidity does not come from the token. Many 2018–2020 STOs found few buyers on secondary venues. Plan for holders to stay to maturity or exit.
- Small raises struggle. Legal and servicing costs are largely fixed. STOs have worked best for instruments with an existing investor base.
- Standards beat custom code. Proprietary token designs locked issuers into one vendor. ERC-3643 and similar open standards have made tokens more portable.
- Institutions drove the recovery. The current growth is in tokenized funds and debt from established managers, not startup equity.
Frequently asked questions
Can a startup raise its seed round as an STO?
It can, usually via Reg D or Reg CF in the US, but tokenization adds cost and complexity. It makes most sense if you expect many investors and future transfers that a token register would simplify.
Do STO tokens trade on crypto exchanges?
Not on ordinary crypto exchanges. Security tokens trade on licensed venues, such as an ATS in the US or an MTF or DLT market infrastructure in the EU, and only between eligible holders.
Is an STO cheaper than a traditional private placement?
Rarely at first. The legal work is similar, and you add technology and audits. Savings appear later in administration and transfers when there are many holders.
Does MiCA cover security tokens?
No. MiCA excludes crypto-assets that qualify as financial instruments. Those remain under existing EU securities law.