Marketplace outbound gets run as though it were B2B SaaS outbound with a different product, and it is a different problem.
A SaaS company wants more customers anywhere. A marketplace wants enough of the scarce side in one specific place to make the other side’s experience work. A hundred suppliers spread across twelve cities is worth less than twenty in one, the hundred produce twelve broken marketplaces and the twenty produce one working one.
So density beats volume, and that single fact reorganises everything below.
Which side to target, and when it changes
The constraint moves, and your outbound target has to move with it.
Early: almost always supply. Demand will not tolerate an empty marketplace, so supply comes first even though it is the less valuable side.
Growing: whichever side is causing failed transactions. The diagnostic question is what a failure looks like, searches with no results means too little supply; suppliers with no bookings means too little demand.
Mature: usually demand, plus selective supply in specific categories or geographies where you have gaps.
The practical implication: your outbound target should be reviewed monthly against liquidity data, not set annually. A team still running supply acquisition six months after supply became abundant is manufacturing churn, suppliers who join, get nothing, and leave annoyed.
By geography, not in aggregate. The national picture is almost always misleading. You may be supply-constrained in Manchester and demand-constrained in London in the same week, and an aggregate view shows neither. Build the view by postcode, city or whatever your unit of liquidity actually is.
Supply-side outreach is closer to recruitment than to sales
The most useful reframing in this post.
You are approaching a small business owner, a sole trader or an independent professional and asking them to invest time setting up, learning your process and changing how they get work. There is no product to evaluate. The offer is “more customers”, which every platform claims.
What follows from that:
Volume is high and value per acquisition is low. Hundreds or thousands of approaches per cohort, against a lifetime value that might be modest. This is the one segment in this series where automation genuinely matters more than personalisation, because the economics do not support a researched message per prospect.
The audience is small businesses, which changes the rules. Sole traders, partnerships and individuals are treated differently from corporate recipients under several countries’ electronic marketing rules, in the UK, for instance, the restrictions that do not apply to corporate subscribers do apply to sole traders and most partnerships. If your supply side is individuals rather than companies, your compliance position is materially different from ordinary B2B outbound. Selling into Europe from outside it covers the distinction, and this is a get-advice point rather than a read-a-post point.
Channels follow the trade, not best practice. Tradespeople answer phones and WhatsApp, and ignore email. Creative freelancers live in email and Instagram. Restaurant owners are reachable by phone in the afternoon and never at 7pm. Clinic owners are reachable through their practice manager. Pick channels per supplier type rather than running one playbook.
Churn is the real enemy. Acquiring a supplier who leaves in six weeks costs you twice, the acquisition spend and the damage from a bad experience they will describe to peers in a small community. Supplier communities talk, and in a trade or a city they talk a lot.
Proof of demand is the only message that works
Everything else is a variation on “more customers”, which they have heard from four platforms this month.
What works is specific, local, current demand:
- “We’ve had 34 requests for [service] in [specific area] this month that we couldn’t fill.”
- “Three customers within two miles are looking for [service] right now.”
- “Your category gets about 60 searches a week here and we have four providers.”
That is not a value proposition. It is a fact about unmet demand they could serve this week, and it is the only thing that reliably converts a supplier who is already busy.
The operational requirement: you need the demand data per geography and category, and you need it in the message. Which means the outbound system has to be fed by your own liquidity data rather than by a static list. This is the piece most marketplaces never build, and it is the difference between a 2% and a 15% response rate on supply acquisition.
Three supporting messages, in order of effectiveness:
- Unfilled demand, as above. Strongest by a distance.
- Competitor dissatisfaction. Suppliers on other platforms complain about commission, lead quality and payment timing. Addressing the specific complaint in their trade is effective.
- Fill-the-gaps positioning. “Use us for your quiet Tuesdays” is a lower-commitment ask than “switch to us”, and low commitment is what gets a busy supplier to try.
And one to avoid: do not lead with commission rate. It invites a comparison on price with an incumbent who has their existing earnings, and you will lose it.
Demand-side outbound
Different problem, closer to conventional B2B, if your demand side is businesses.
For B2B marketplaces, ordinary outbound applies with one adjustment: your pitch is supply depth in their specific need, which means the same data problem in reverse. “We have eleven vetted [specialists] in [your city] available this month” is the version that works.
For consumer demand, outbound is largely the wrong tool. That is a marketing problem, search, paid, local SEO, partnerships.
The exception worth knowing: small-business demand often looks consumer-shaped but is reachable by outbound. A café needing equipment servicing, a clinic needing locum cover, an office needing cleaning. These are businesses with findable contact details and recurring needs, and most marketplaces treat them as a marketing audience when they are an outbound one.
Sequencing supply acquisition properly
Density is the objective, so launch by geography.
1. Pick one area and define it narrowly. A city, or a district of a large one.
2. Count what you need. Enough suppliers in each category to serve expected demand with margin. Usually a smaller number than people assume, often ten to thirty per category rather than hundreds.
3. Build the complete local list. All of them, not a sample. For a defined area and category this is a finite, knowable set: directories, maps data, trade registers, review sites. Completeness is achievable here in a way it never is in B2B.
4. Work it hard, with multiple channels and several touches. You are not optimising for efficiency per prospect; you are optimising for coverage of a finite list.
5. Measure liquidity, not sign-ups. Can demand be served in that area now? That is the only question.
6. Then move to the next area and reuse the playbook.
This is the opposite of the conventional advice to run broad campaigns and let the responses tell you where to focus. Broad campaigns produce thin coverage everywhere, and thin coverage is worth nothing in a marketplace.
Automate the refill. New suppliers appear constantly, businesses open, people go independent. A saved search that surfaces new businesses in your covered areas and enrols them automatically keeps coverage current without anyone running a quarterly list build. Campaigns that refill themselves covers the mechanics.
The metrics that replace meetings
Standard outbound metrics do not describe this funnel. Five that do.
Cost per activated supplier, where activated means completed onboarding and available to take work, not signed up. Sign-ups are a vanity number in marketplaces; the gap between sign-up and activation is usually where the money is lost.
Time to first transaction. The strongest predictor of supplier retention. A supplier who gets work in week one stays; a supplier who waits a month leaves. If this number is long, your sequencing is wrong, you are acquiring supply ahead of demand.
Supply density per geography and category. The operational metric. Acquisition is the input; this is the output.
Fill rate. The proportion of demand you can serve. The number that tells you which side to target next month.
90-day supplier retention, by acquisition channel. This one exposes bad acquisition. A channel producing cheap sign-ups that churn at 70% is more expensive than an apparently costly channel producing suppliers who stay, and only this metric shows it.
That last one is worth building first. Marketplace acquisition goes wrong most often by optimising cost per sign-up, which is the one number that can be improved by acquiring worse suppliers. What a lead actually costs covers the general version of that trap.
The short version
Density beats volume. Twenty suppliers in one city are worth more than a hundred across twelve, so launch by geography and measure liquidity rather than sign-ups.
Review which side you are targeting monthly against liquidity data, broken down by area rather than nationally. Supply early, then whichever side is causing failed transactions.
Supply acquisition is closer to recruitment than sales: high volume, low value per acquisition, channels chosen per trade, and a compliance position that differs from ordinary B2B because sole traders and individuals are treated differently from corporate recipients.
Proof of local unmet demand is the only message that reliably works, which means feeding your outbound from your own liquidity data.
And measure cost per activated supplier plus 90-day retention by channel, because cost per sign-up can always be improved by acquiring worse suppliers.
Next: campaigns that refill themselves, or outbound for recruiters, which shares the two-funnel structure.
Frequently asked questions
Which side of a marketplace should you target with outbound?
Supply early, since demand will not tolerate an empty marketplace, then whichever side is causing failed transactions, searches with no results mean too little supply, suppliers with no bookings mean too little demand. Review it monthly by geography rather than nationally.
What message works for marketplace supply acquisition?
Specific, local, current unmet demand: how many requests in their area you could not fill this month. “More customers” is what every competing platform says, so only concrete demand data converts a supplier who is already busy.
Is marketplace outbound different from B2B outbound?
Yes. The objective is liquidity density in a defined area rather than pipeline in general, volume is high with low value per acquisition so automation matters more than personalisation, and the supply side is often sole traders and individuals, who fall under different electronic marketing rules than corporate recipients.
What metrics matter for marketplace outbound?
Cost per activated supplier rather than per sign-up, time to first transaction, supply density per geography and category, fill rate, and 90-day retention by acquisition channel. Cost per sign-up is misleading because it improves when you acquire worse suppliers.