A company list for Switzerland is quickly bought. Whether it suits your purpose only becomes clear during the import or on the first call. These eight checks help you compare offers beforehand, and the four warning signs at the end help you spot dubious ones.

1. Where does the data come from?

Ask about each source separately. The commercial register is public, and the Federal Commercial Registry Office publishes its entries as open government data that may be used with attribution. The register does not contain phone numbers or email addresses, though. These come from websites, map data or directories. Many telephone and business directories prohibit building address databases in their terms of use. A provider should be able to explain which source supplies which field.

2. Which reference date applies?

A date on the website is not a check date for every row. Ask when the data was last taken from the sources and whether companies deleted from the commercial register are removed. In hospitality and retail, operators and phone numbers change particularly often.

3. How does the provider handle the asterisk marking?

In Switzerland this is the most important point for telephone prospecting. It is unfair to disregard the note in the telephone directory that someone does not wish to receive advertising and that their data may not be passed on for direct marketing. Anyone without a directory entry is treated like someone with an asterisk (Art. 3 para. 1 let. u UWG). A list for telephone marketing without a check against the asterisk marking is therefore worthless to you and risky for the provider. Ask how and on which date the check was made.

4. What about email addresses?

In Switzerland, mass advertising by email, SMS or fax requires the recipients’ prior consent, even if they are businesses (Art. 3 para. 1 let. o UWG). A purchased list contains no such consent. Email addresses are still useful, for example to match records in your CRM or to look after existing customer relationships. Do not buy them as a campaign channel.

5. Is there a unique key?

In Switzerland this is the business identification number (UID, format CHE-123.456.789). It identifies a legal entity permanently and is not reassigned after deletion (Art. 116 HRegV). A list with UIDs can be matched cleanly against your CRM. Unregistered sole proprietorships often have no UID; additional attributes are needed there.

6. Which fields are filled how often?

A total number of companies says little. What matters is how many records contain all the fields you need, for example a phone number without an asterisk and a website in a particular canton. Ask for the count after all filters, not for percentages across the whole database.

7. What does a usable record cost?

Divide the price by the number of records you can actually use. A cheap list full of holding companies without staff, duplicates or numbers with an asterisk ends up more expensive than a smaller, clean selection.

8. What may you do with the data?

Clarify whether you may use the data permanently, store it in several systems or pass it on to partners. Data on sole proprietorships and named individuals are personal data. If you do not collect them from the person concerned, you generally have to inform that person of the collection within one month (Art. 19 FADP); exceptions are set out in Art. 20 FADP. An express objection must be respected (Art. 30 para. 2 let. b FADP).

Four warning signs

  • “Email addresses with consent” without proof of who consented to whom and when.
  • “Phone numbers from the commercial register”: the register contains no phone numbers.
  • “100 % up to date” or “checked daily” for hundreds of thousands of records.
  • No sample file: a provider who does not show the file structure cannot guarantee it later either.

How we handle it

kontaktdatenbank.ch has been building its Swiss company database since October 2026. We name the sources on the page Data sources and methodology, show the file structure in a sample file with fictitious companies and confirm scope, reference date and price before every order. We currently deliver phone numbers only as “not checked”, so not for telephone marketing.