Mobile number enrichment is the process of adding a direct mobile to a B2B contact record from one or several data providers. It is the single biggest lever on connect rate after timing, because a switchboard number is not a conversation, it is a gatekeeper. Here is what match rates really mean, how to test a provider in a week, and the GDPR basis that makes it legal in France and Europe.

What a match rate hides

A provider that announces "90% match rate" is usually counting any field it returned: an email, a switchboard, a city. The number you care about is narrower: what share of your contacts got a direct mobile that rings, in your market, for your personas.

Three things move that number more than the provider's logo. Geography: coverage in France, Germany or the Nordics is structurally lower than in the US and UK, because fewer people publish numbers and privacy rules are stricter. Function: sales and marketing profiles are over-represented in every database; finance, legal and technical roles are thinner. Company size: SMB contacts are harder than enterprise ones, because fewer sources index them.

In France there is a simple sanity check: a mobile starts with 06 or 07. Anything starting with 01 to 05 or 09 is a landline or a virtual number, and most of those are switchboards. Count only the 06 and 07 lines when you compute your real match rate.

Why mobile coverage is the connect-rate lever

Our benchmark of 1,000,000 B2B cold calls in France puts the average connect rate at 11.3%, with a range of 11% to 20% depending on persona and time slot. In our experience, direct mobiles connect several times more often than switchboard numbers, because the switchboard call ends at reception or in a generic voicemail, and the mobile call reaches the person.

That gap compounds. A rep making 100 dials at a switchboard-heavy list and a rep making 100 dials at a mobile-heavy list are not doing the same job, even with the same script and the same 4pm slot (15.8% pickup across personas in our data). Mobile coverage is why two teams with the same dialer get different results.

The 100-contact test: how to evaluate a provider in a week

Do not trust a benchmark, including this article. Run your own.

1. Pull 100 contacts that represent your real ICP: the right countries, the right functions, the right company sizes. Do not pick the easy ones.
2. Run them through each provider you are evaluating, on the same day.
3. Count direct mobiles only (06/07 in France, equivalent patterns elsewhere), not total fields returned.
4. Call every number returned over two days, in your best slots. Count connects with the right person, not rings.
5. Compute cost per reachable contact: total spend divided by contacts you actually connected with.

The last number is the only one that matters. A provider with a lower headline match rate and a higher reachable rate is the better provider.

The GDPR framework for phone enrichment in Europe

B2B phone enrichment is legal in France and the EU, under conditions. This is how we understand them; check with your counsel.

• Legal basis: legitimate interest, not consent. Prospecting professionals about their professional activity is a recognised legitimate interest. You do not need prior opt-in for B2B calls. Consumers are different: since 11 August 2026, French law requires prior consent to cold call a consumer.
• Information duty (Article 14). When data does not come from the person, you must tell them where it came from, at the latest at first contact. A sentence on the call and a privacy page that names your data sources cover it.
• Right to object. One request, immediate removal, documented, never called again.
• Retention. CNIL guidance sets a maximum of three years after the last contact for prospect data. Older data is also dead data; purging it raises your answer rate.
• Documentation. Keep your legitimate interest assessment, your provider contracts and your data-source list. If a contact or the CNIL asks, you answer in a day.

Enrich on demand rather than in bulk. A number found in January and called in June is a number that may have changed, and bulk enrichment of contacts you never call is hard to justify under data minimisation.

How Sonik approaches mobile data

Sonik does not sell phone data; it makes sure the data you have gets called at the right time. The dialer flags switchboard and invalid numbers after each attempt, so the list cleans itself, and it feeds connect outcomes back by number type, persona and slot. You see, per provider, which numbers actually reach people.

Enrichment happens when a signal fires, not months before. When a contact changes jobs or an account visits the pricing page, the record is refreshed before it hits the rep's list. Parallel dialing then calls the mobile list about five times faster than manual dialing, which is what turns a 15% connect rate into 20 conversations a day. See the Sonik dialer.

And because we are a French company calling French numbers under French rules, the data-source sentence, the opt-out handling and the retention clock are built into the workflow, not left to each rep.

Conclusion

Match rate is a marketing number; reachable rate is a sales number. Count only direct mobiles, call them, and divide spend by connects. Under GDPR, legitimate interest plus transparency plus fast opt-outs is enough for B2B. This week, run the 100-contact test on your current provider and compute your real cost per reachable contact.