German online broker retail investor data (restricted access)

Confidential single-counterparty data: not exercised here

This is confidential data from a single online broker. It is not for sale, not publicly downloadable, and not re-obtainable without the same agreement: it carries no provenance badge because there is no access path we can run here. Researchers obtained it under a confidential agreement with the broker, which is kept anonymous. The page documents what the data is and the gotchas; treat it as unverified. This is the honest grade under the institute’s Verified discipline.

The online-broker data is the account-level record of retail investors at one anonymous German online brokerage: security holdings, trades, portfolio characteristics, and returns over a multi-year window. It is one of the recurring sources for German retail-investor behavior, valued because it observes actual holdings and trades rather than survey-reported intentions. A paper we distill uses it: Laudenbach, Malmendier & Niessen-Ruenzi use the online-broker data (839,292 investor-year observations for 230,229 retail investors, 2004 to 2012; holdings, portfolio characteristics, and returns, with Datastream returns merged in) to study how growing up under communism shapes financial attitudes.

• Cost: not for sale. Confidential single-counterparty data.
• Source: an anonymous German online broker.
• Coverage: the broker’s own clients, not the German population; account-level holdings, trades, and returns over the sample window.

Access (restricted)

• No public download and no resale. The data is the broker’s confidential client records; it cannot be purchased or redistributed.
• Through a confidential agreement with the broker. Access required a research agreement, and the broker’s identity is not disclosed. There is no standing way for a third party to reach the same data.

Gotchas (the ones that bite pipelines)

These are the failure modes to expect; they are documented, not verified here.

• One broker is a selected clientele. Online-broker clients self-select on being active, online, and direct investors; they are not representative of all German households or investors. Do not generalize portfolio behavior to the population.
• Holdings at this broker, not total wealth. The account shows assets held at this broker, not the investor’s whole portfolio or non-traded wealth; apparent concentration or risk-taking can be an artifact of partial coverage. Treat it as one account.
• Returns need an external price source. Position-level returns are computed by merging an external price/return feed (here Datastream); corporate actions and mergers must be handled or returns are mismeasured.
• Demographics are limited and sometimes imputed. Investor characteristics are thinner than in administrative registers and may be merged from municipality-level sources; do not treat imputed demographics as individual ground truth.
• Not redistributable and broker stays anonymous. Results can be reported but the microdata cannot be shared and the broker is not named, limiting external replication. Plan for non-reproducibility of the raw inputs.

Citation

Cite the source and arrangement, e.g.: Retail online-broker account data (anonymous German broker), confidential; used under agreement, YYYY-MM-DD. State the sample window, the unit (investor-year), and the external return source used.