According to CoinMeta, SEC requires that smart contracts used by tokenized securities platforms (TSV) must be auditable and transparent, and must be deployed on public, permissionless distributed ledgers. TSV must suspend trading of tokenized NMS stocks in sync with the main listing exchange of those stocks, and must make public disclosures regarding its own operations, trading activities, and those of its associated parties. For stocks that are tokenized by unrelated third parties, TSV is required to provide prior written notice and an opportunity to object to the issuer. This exemption will expire after five years from the date of announcement. (Source: SEC)