Which entity's guidelines require verification of customers' identities conducting significant transactions?

The correct choice relates to the Financial Action Task Force (FATF), which sets international standards and guidelines to combat money laundering and the financing of terrorism. FATF's recommendations emphasize the importance of conducting customer due diligence (CDD) and verifying the identities of customers, especially when significant transactions are involved. This is fundamental in preventing illicit activities and ensuring that institutions are not facilitating money laundering.

When a financial institution or service provider engages in significant transactions, FATF guidelines advocate for a robust approach to verifying customer identities and understanding the nature of the transactions. This helps to mitigate risks associated with money laundering and other financial crimes.

The other entities listed have distinct roles within the financial regulatory environment; for instance, OFAC focuses on sanctioning foreign nations and entities, while the SEC oversees securities markets, and FinCEN focuses on domestic financial crimes, including money laundering but operates within a different regulatory framework. Nevertheless, the FATF is particularly known for establishing the standard practices related to customer identity verification in the context of significant transactions.