Under the rules, mutual funds and other investment companies are required to file certain advertisements for review by the Financial Industry Regulatory Authority (Finra).

But the SEC says that firms are showing an 'abundance of caution' in their interpretation of the guidelines and are filing too much material for review with Finra.

The updated guidance provides examples of the kinds of communications that the SEC believes would fall foul of the rules, and social posts that would not trigger a filing requirement.

Norm Champ, director of the division of investment management, says: "Today's inaugural IM Guidance Update on social media is intended to help firms strengthen their compliance efforts by providing meaningful real life examples in a format that is accessible to all on the SEC's website."

Read the guidance update:» Download the document now 1.6 mb (PDF File)