French financial regulator AMF has published a study on the behaviour of retail investors in CAC 40 stocks in the age of social media.

The AMF stated that a rise in retail investment has been accompanied by changes in the ways in which investors obtain information and support. Whilst bank advisers remain the primary source of information for investors, social media is playing an increasingly significant role in their decision-making processes, particularly amongst younger investors.

The growth in retail stock market trading in recent years has been accompanied by a rise in interest in finance and investment-related topics on social media. According to the AMF’s Savings and Investment Barometer published in December 2025, 12% of French investors consult financial institutions’ social media accounts and posts before investing. Whilst bank advisers remain the primary source of information, social media is playing an increasingly significant role in investment decisions.

This trend is particularly pronounced among 18-24-year-olds, a less experienced demographic: 41% say they obtain information via this channel, according to a study carried out by the OECD for the AMF (published in November 2023).

Analytical framework: comparison of behaviour by age and investment firm

In order to better understand these new investment behaviours, the AMF study aims at analysing the influence of the social media platform X (formerly Twitter) on the activity of retail investors trading in CAC 40 stocks held directly, between January and November 2024. Social media activity is measured by the daily number of posts on X, as well as the sentiment (positive, negative or neutral) expressed therein.

The study is based on an analysis of transaction reporting data submitted to the AMF, which provides a comprehensive overview of transactions carried out by European investment service providers in securities falling within its remit. According to the AMF, the richness of the data makes it possible, in particular, to analyse investors’ trading flows by age, comparing investors aged over and under 35, as well as by the type of intermediary used to execute trades, distinguishing between traditional banks, 100% online banks and neo-brokers.

The analysis takes social media into account as a source of information likely to influence investors, whilst also assessing the influence of more fundamental variables such as share price levels and issuers’ corporate communications.

Key findings: younger investors and clients of neo-brokers are more responsive to information shared on social media

French retail investors buy shares when prices fall and sell when they rise. This contrariant behaviour is consistent with previous academic findings on the subject and may reflect a desire to lock in realised profits. Retail investors also tend to be more active when volatility increases.

Investors are more sensitive to the number of posts on social media than to their content. The tone of the posts – that is, whether they express a positive or negative opinion – does not appear to influence trading activity.

Younger investors and those most familiar with digital tools are the most responsive to social media. It therefore appears that younger investors and the clientele of neo-brokers tend, overall, to underreact to fundamental information (i.e. the price or communications released by issuers). Their behaviour is thus less sensitive to the economic backdrop. Conversely, online banking customers are the most likely to adjust their behaviour in response to fundamental information.

Conversely, younger investors and clients of neo-brokers overreact to messages posted on social media:

• either they are the only ones to increase their activity when the volume of posts rises;
• or, when an increase in activity is observed amongst all investors, their reaction is more pronounced: the increase in their activity is twice as large as that of other investors.

Customers of traditional banks are the least responsive to social media, a finding consistent with the fact that they are likely to comprise more experienced investors who are less inclined to turn to social media.

The study supports the AMF’s strategy on investor protection

The results of the study highlight the importance for the AMF of continuing to support investors, particularly younger ones, by encouraging them to carry out thorough research before investing, drawing on reliable and diverse sources. In particular, in 2023, the AMF, in collaboration with the Advertising Regulatory Authority (ARPP), launched a certificate in responsible influence in finance.

The AMF’s report The influence of social media on retail investor trading in CAC 40 stocks can be downloaded here.