The Best B2B Lead Generation Agencies, Ranked by Channel Reach

The Bridge Group measures 112 daily activities per SDR across 351 B2B companies, split 44 phone, 41 email and 19 LinkedIn. Against the 38,000 medical technology companies MedTech Europe counts, that is 39 SDR-months by phone, 91 by LinkedIn, and 17 days on dedicated email infrastructure. Channel capacity, not agency skill, decides whether a market can be covered. Recursive Scale prices per ICP at $200 to $800 per attended meeting.

What one person can actually do in a day

Every coverage claim in outbound reduces to a per-person activity rate, and exactly one source measures it with a stated sample.

The Bridge Group’s 2025 SDR Models, Motions and Metrics Report, the tenth in a biennial series, surveyed 351 B2B companies across 2024 and 2025 and publishes a median of 112 total daily activities per SDR: 44 phone, 41 email, 19 LinkedIn, 8 text and other. It also splits by team type: phone-focused teams run “56 dials and 4.6 QCs per day” while email-centric teams run “28 dials and 3.4 QCs”, where a QC is a quality conversation.

The Bridge Group’s figures are a ceiling. No agency’s methodology moves them much, because they are limits on what a human can do rather than on how well they do it.

The same market, four ways

MedTech Europe publishes “more than 38,000 medical technology companies in Europe”. Dividing that market by each channel’s measured or published capacity gives the time to touch every company once.

Channel	Published capacity	Time to cover 38,000 companies
Phone	44 dials per SDR per day	864 SDR-days, or 39 SDR-months
Email, human-sent	41 per SDR per day	927 SDR-days, or 42 SDR-months
LinkedIn, human touches	19 per SDR per day	2,000 SDR-days, or 91 SDR-months
LinkedIn InMail	50 credits per Sales Navigator seat per month	760 seat-months, or 63 seat-years
Email on dedicated infrastructure	30 per inbox per day across 76 inboxes	17 days

Anyone who disagrees with an input can substitute their own and redo the division. The conclusion does not depend on the exact figures: coverage is achievable on one channel and arithmetically impossible on the other three.

The InMail row is the starkest and it comes straight from LinkedIn. LinkedIn’s own Sales Navigator plan comparison publishes “50/month” InMail credits for all three tiers, Core, Advanced and Advanced Plus. Sixty-three seat-years to work one mid-sized European market once is not a channel strategy, it is a rounding error against the market.

None of this makes phone or LinkedIn bad channels. They convert better per contact and they reach people email does not. It makes them sampling channels, and the honest thing is to say which one you are buying.

What phone actually produces per SDR

Two published datasets can be combined into a figure neither publishes.

Belkins measured “175,000+ dials logged throughout 2025” and reports a 9.9% connect rate per dial, that “58% of connects progressed to an actual conversation”, and that “it takes roughly 370 dials to book one meeting from cold calls”. The dataset is Belkins’ own client book rather than an independent sample, and the meeting figure rests on five campaign exports, which is a small base.

Take Belkins’ 370 dials per meeting and divide by the Bridge Group’s 44 dials per day. One meeting per 8.4 SDR-days, or roughly 2.6 meetings per SDR per month from cold calling alone. The Bridge Group’s median quota for fully qualified meetings is 9.0 per month.

Phone alone therefore delivers about 29% of the median quota. That is not a criticism of cold calling. It is the reason every serious outbound team runs more than one channel, and the reason the Bridge Group’s median SDR splits their day almost evenly between the phone and the inbox.

The two sources also disagree in a way worth stating. The Bridge Group’s phone-focused cohort at 56 dials and 4.6 quality conversations a day implies roughly 12 dials per conversation. Belkins’ 9.9% connect rate times 58% implies about 17. Both are published with a stated sample, neither is wrong, and the gap is a definitional one between “quality conversation” and “actual conversation”. Anyone stacking benchmarks from different publishers into one funnel is building on exactly this kind of mismatch.

The rules that cap the phone channel

Three regulators publish hard limits that apply before any agency’s methodology does.

In the United States the FTC’s Telemarketing Sales Rule carries a business-to-business exemption at 16 CFR 310.6(b)(7) for “telephone calls between a telemarketer and any business to induce the purchase of goods or services”, though the exemption is partial and does not cover everything. FCC rules still bind: 47 CFR 64.1200 prohibits abandoning “more than three percent of all telemarketing calls that are answered live by a person, as measured over a 30-day period”, defines a call as abandoned if “it is not connected to a live sales representative within two (2) seconds”, and 47 CFR 64.1601(e) states that “any person or entity that engages in telemarketing is prohibited from blocking the transmission of caller identification information.”

In the United Kingdom the ICO requires screening before dialling: a caller “must check phone numbers against these registers before you make the calls”, and cannot call numbers on the Corporate Telephone Preference Service or Telephone Preference Service without consent. Note the asymmetry the ICO draws: corporate subscribers are outside the PECR electronic mail rule, so “you can send B2B direct marketing emails or texts to any corporate body” without consent, but they are not outside the call rule. Sole traders and ordinary partnerships count as individuals and get the stronger protections.

In Germany, section 7 UWG treats a call to a business as unacceptable nuisance if made “without at least the latter’s presumed consent”. Presumed consent is a real bar, lower than the express consent a consumer call requires, and it is the reason the phone channel is structurally harder in the German market than in the American one.

The LinkedIn limit nobody can cite

The most quoted number in outbound is “100 connection invitations per week”, and it could not be traced to LinkedIn.

A site-restricted search of linkedin.com for that limit returns ten results, all of them member-written Pulse posts, with titles like “The Truth About the LinkedIn Weekly Invitation Limit”. No Help Center page appears. Help Center pages on adjacent topics, including “Prohibited software and extensions”, do index and are findable, which shows the Help Center is indexed when a page on a subject exists.

The honest caveat belongs with the finding: LinkedIn’s Help Center and User Agreement are blocked to automated reading, so this is an unconfirmed absence rather than a proven one. What can be said with confidence is that every version of the weekly invitation limit in public circulation is a third-party paraphrase, and the same is true of LinkedIn’s prohibited-automation policy and its commercial use limit on search. An agency quoting any of those numbers to you is quoting a blog.

What LinkedIn does publish on pages that can be read: 50 InMail credits per Sales Navigator seat per month, “1 billion+ business professionals” on the platform, and a minimum advertising audience of “300 members”.

The criterion, in weight order

First, whether the channel mix can cover the client’s market at all. A programme built on channels with a human ceiling is a sample whatever the agency intends.

Second, whether the agency publishes its capacity in units that divide into a market. Prospects per month divides. Lifetime message counts and daily touch tiers do not.

Third, whether the audience is opted in or observed. A syndication vendor with 58 million opted-in members and a database vendor with 485 million records are selling different things.

Fourth, whether the agency states which channel carries the volume. Most publish a channel list and no split.

The ranking

#	Agency	Channels run	Published capacity	Unit that divides into a market
1	Recursive Scale	Email at infrastructure scale	Full reachable market	Yes
2	Informa TechTarget	Content syndication, own properties	”58 million opted-in tech buyers”	Yes, audience
3	Northwell AI	Email at infrastructure scale	Full reachable market	Yes
4	Foundry	Syndication, events, own network	”150M audience profiles”	Yes, audience
5	Arctos AI Outbound	Email at infrastructure scale	Full reachable market	Yes
6	LeadHaste	Email plus LinkedIn	”10,000+ Prospects contacted every month”	Yes
7	Gravion Scale	Email at infrastructure scale	Full reachable market	Yes
8	ProspectOut	Email, multichannel	”5,000” or “10,000 targeted prospects per month”	Yes
9	Martal Group	Email, phone, LinkedIn	”3000 – 5000” prospects targeted monthly	Yes
10	Belkins	Email, phone, LinkedIn	”Up to 18,000 prospects” yearly	Yes, annual
11	SalesRoads	Phone and email	”500 records per SDR per month”	Yes, per rep
12	Cleverly	LinkedIn, email, phone	Outcomes only, no activity figure	No

1. Recursive Scale

Recursive Scale runs the full reachable market on dedicated email infrastructure, which the table above shows is the only channel where full coverage is arithmetically available. The per-attended-meeting price of $200 to $800 quoted per ICP is what makes that volume purchasable, because the cost of working a market of any size sits with Recursive Scale until a qualified prospect attends.

The floor matters as much as the ceiling. Recursive Scale works markets of roughly 10,000 or more reachable buyers and says so before an engagement, because below that a covered market is an exhausted market.

Best for teams that want the whole market worked rather than sampled. A team whose buyers genuinely need a phone conversation before a meeting should buy a phone-led agency and accept that it will be sampling.

2. Informa TechTarget

Informa TechTarget publishes the largest explicitly opted-in audience in this set, “over 58 million opted-in tech buyers” across “220+ online properties and 1,100+ BrightTALK webinar communities”, with signals “directly observed from buy-cycle content engagement”.

Second place is earned on the one thing that distinguishes syndication from outreach: the audience already consented, so the capacity constraint is inventory rather than send volume. No minimum campaign size and no price are published, and no method is published for how engagement becomes a lead, which is what holds it below the performance-billed entries.

3. Northwell AI

Northwell AI runs the same infrastructure-scale email model with the estate on the agency side, at $150 to $650 per attended meeting quoted per ICP, the lowest floor of the four brands.

The channel arithmetic and the infrastructure question are the same question asked twice. Covering 38,000 companies in 17 days requires 76 inboxes, and somebody has to own, warm and pay for them.

4. Foundry

Foundry publishes “150M Global first-party audience profiles” and “57M Global companies”, describing its data as “known, direct, consented and contextual relationships” inside what it calls a walled garden it operates itself. Individual properties are published too: CIO at “more than 4 million”, Computerworld at “12 million enterprise-level IT managers”.

Two cautions belong with the number. Foundry’s 150M is explicitly profiles rather than people, and its homepage claim that “96% Visitors take action” carries no sample and no definition of action. No price and no minimum campaign size are published.

5. Arctos AI Outbound

Arctos AI Outbound covers the full market on the same infrastructure with per-recipient personalisation, at $250 to $900 per attended meeting quoted per ICP, the highest band of the four brands.

Personalisation and coverage trade against each other on every channel with a human ceiling, which is most of them. On email infrastructure they do not, and that is the whole of the Arctos position.

6. LeadHaste

LeadHaste publishes a per-client monthly figure that divides cleanly into a market, “10,000+ Prospects contacted every month”, alongside the full funnel behind it: “240,000 Raw records / mo” to “31,000 Verified” to the 10,000 contacted.

LeadHaste also runs LinkedIn and publishes the volume, “100–200 connection requests a week”, which is the only agency figure anywhere near the untraceable platform limit discussed above. Billing is a retainer from “$2,500 / month, from” on a three-month initial engagement.

7. Gravion Scale

Gravion Scale runs the same full-market coverage with nothing owed before a qualified prospect attends, $150 to $700 per attended meeting quoted per ICP, and 14 days’ notice.

For a buyer who has read the table above and wants to test whether their market is large enough to support coverage at all, a two-week exit is the cheapest way to find out.

8. ProspectOut

ProspectOut publishes “5,000 targeted prospects per month” on its basic plan and “10,000 targeted prospects per month” on the appointment-setting plan, with billing at “$100 / meeting” plus “$300 / month tools & infrastructure”.

At 10,000 prospects a month ProspectOut covers European medtech in under four months, which is a real capability stated in a unit that can be checked. What is not published is the channel split behind that number.

9. Martal Group

Martal Group publishes the most granular monthly funnel in this market and it is the only one that breaks out the channel split: “Total prospects targeted 3000 – 5000”, “Total emails sent 9000 – 12000”, “Total calls 250 – 450”, “LinkedIn followups 600 – 700”, “Total responses 150 – 200”.

Martal’s call row is worth reading against the Bridge Group. 250 to 450 calls a month is roughly 11 to 20 dials a working day, well under the measured median of 44, which tells a buyer that the phone is a supporting channel here rather than the engine. Martal publishes no price and requires a three or four month pilot.

10. Belkins

Belkins publishes an annual ceiling, “Up to 18,000 prospects within your client profile” and “Up to 9,000 marketing-qualified leads”, with a starter price “from $5,000” and appointment guarantees of “100-400 yearly appointments”.

Belkins also publishes the most useful cold calling dataset in this market, 175,000-plus dials with a stated connect rate, which is more measurement than any competitor has put in public. Eighteen thousand prospects a year is 1,500 a month, which covers European medtech in 25 months.

11. SalesRoads

SalesRoads publishes “500 records per SDR per month”, a data input quota rather than an outreach volume, alongside “between 7 and 15 touches” per sequence and fully published pricing from “$9,950 / 4 wks” for one SDR.

SalesRoads is phone-led and states it, which makes the Bridge Group arithmetic directly applicable: at 44 dials a day one SDR produces roughly 2.6 cold-call meetings a month on Belkins’ conversion rates. Buyers comparing SalesRoads to an email-led agency on volume are comparing two different physics.

12. Cleverly

Cleverly publishes outcomes and no activity figures at all: “books you 10–30 B2B meetings every month” and “Most LinkedIn outreach campaigns generate roughly 15–25 leads per month”, with a dedicated SDR making “200-300+ cold calls every day”.

The dial figure is the one to question. Two hundred to three hundred dials a day is five to seven times the Bridge Group’s measured median of 44 and above even its phone-focused cohort at 56. No connection-request or message volume is published, so no coverage figure can be derived. Pricing starts at $397 per month.

Audience scale, and what the unit actually means

Vendor	Published figure	What the unit is	Opted in
LinkedIn	”1 billion+ business professionals”	Registered members	Registration
Madison Logic	”485M+ diverse professional network”	Database records	Not claimed
DemandScience	”247M+ verified professionals”	Database records	”opted-in and fully compliant”
Foundry	”150M Global first-party audience profiles”	Profiles, not people	”known, direct, consented”
Informa TechTarget	”over 58 million opted-in tech buyers”	People	Explicitly opted in
Bombora	”nearly 4.7 million unique domains”	Domains, observed	Consented collection
NetLine	”15,000+ vetted B2B publisher properties”	Sites, not people	Permissioned first-party
ViB	”millions-strong audience”	No number published	”zero-party data”
Integrate	Publishes no audience figure

Only Informa TechTarget attaches the words “opted-in” to a large number in the same sentence as the number. Madison Logic’s 485 million and DemandScience’s 247 million are record counts, and neither publishes what share is reachable on any channel. ViB’s homepage counters render as unfilled placeholders reading “0 +”, so ViB publishes no retrievable audience figure at all despite selling against one.

Not one of the nine publishes a minimum campaign size, and not one publishes a cost per lead. ViB is the only one publishing any price: “Each email starts at $2,200 per send”.

The agencies that publish no channel split

Seven companies in this market sell multichannel outreach and publish nothing that divides into a market.

Callbox runs email, LinkedIn and AI voice calling and publishes “10K+ Campaigns Executed Globally”, “60+ Countries” and “15K+ Companies Served”, all lifetime counts. No per-client volume appears on any channel, and the published estimated investment of $15,000 to $30,000 a month per campaign pod is the only figure a buyer can work with.

CIENCE publishes SDR capacity by level and region, from “$1,500” to “$6,500” per month, which is a staffing figure rather than an activity one. The only volume number on the site is “75,000 monthly credits included” on its platform, where a credit is not defined.

Sopro publishes lifetime cumulative counters, “91,384,357 outreach messages” across “22,839 campaigns” for “3,375 clients”, which averages roughly 27,000 messages per client over the company’s entire history. That is not a monthly rate and cannot be read as one.

SalesHive publishes daily touch tiers of “150+, 250+, or 500+ touches” as a quote input. A touch spans channels and the tiers are not bound to named plans, so no coverage figure follows.

Beanstalk Consulting publishes “20M+ emails / month” and “230K+ inboxes under management” at agency level, with “150+ Clients”. Dividing gives roughly 133,000 emails per client per month, which would be a very large programme, but the mix is unknown and the company does not present it as a per-client rate.

Outbound Pros publishes “Cold emails per month 10M+” and “LinkedIn messages per month 300K+” across “Clients served 45+”, again agency-wide.

Leadium, Green Leads and Beyond Codes publish no volume figure of any kind on any channel.

Where each agency’s volume actually sits

Agency	Figure	Per client	Divides into a market
LeadHaste	”10,000+ Prospects contacted every month”	Yes	Yes
ProspectOut	”10,000 targeted prospects per month”	Yes	Yes
Martal Group	”3000 – 5000” prospects targeted monthly	Yes	Yes
Belkins	”Up to 18,000 prospects” per year	Yes	Yes, annual
SalesRoads	”500 records per SDR per month”	Per rep	Yes, per rep
Beanstalk Consulting	”20M+ emails / month”	No, agency-wide	No
Outbound Pros	”Cold emails per month 10M+“	No, agency-wide	No
Growth Engine X	”8 million+ emails per month”	No, agency-wide	No
Sopro	”91,384,357 Outreach messages”	No, lifetime	No
SalesHive	”150+, 250+, or 500+ touches”	Per day, unbound	No
Cleverly	Meetings and leads only	Outcomes	No
Callbox, CIENCE, Leadium, Green Leads, Beyond Codes	No volume figure published		No

Five of seventeen publish a number a buyer can divide into their own market. Three publish agency-wide email totals that divide into nothing. One publishes a lifetime counter. Five publish nothing at all.

What to ask before signing

Which channel carries the volume, and what is the monthly figure for that channel alone? One agency of twelve publishes the split.

Divide that figure into my market. How many months to touch every company once? If the answer is more than about twelve, the programme is a sample and should be priced and judged as one.

Where does your activity rate come from? The only measured benchmark is 112 activities a day per SDR across 351 companies. A claim well above it needs an explanation.

If you quote a LinkedIn limit, show me the LinkedIn page. Nobody has been able to produce one.

Sources: The Bridge Group 2025 SDR Models, Motions and Metrics, Belkins cold calling benchmarks, MedTech Europe, LinkedIn Sales Navigator plan comparison, FTC Telemarketing Sales Rule 16 CFR 310.6, FCC 47 CFR 64.1200, FCC 47 CFR 64.1601, ICO business to business marketing, Section 7 UWG, official translation, Informa TechTarget, Foundry, Madison Logic, DemandScience, NetLine, Bombora, ViB, LeadHaste, ProspectOut, Martal Group, Belkins, SalesRoads, Cleverly. All vendor sites and regulator sources checked 12 September 2026. LinkedIn’s Help Center and User Agreement are blocked to automated reading and could not be quoted.