Agree roles in writing before anything is published
Most co-hosting problems are not about the event itself. They come from two organisations each assuming the other was handling something: the invoices, the guest list, the speaker thank-you, the door. A short written agreement, often a single page, settled before the date is announced or any logo goes on an invitation, removes most of these arguments in advance.
Start by giving each organisation a named role, and make sure everyone uses the same words for them. Three roles cover most joint events.
- Lead organiser: owns the event from start to finish. It books the venue, opens registration, usually collects the money, issues invoices and receipts, and reports the final numbers to the others. There is one lead organiser per event, never two.
- Co-host: shares the risk and the reward. It promotes the event to its own members, may contribute to costs or provide staff on the day, and takes an agreed share of any surplus and of any loss.
- Supporting partner: lends its name and its reach but carries no financial risk. It may appear on the invitation and send guests, but it does not share the costs or the surplus.
Decide who takes the money and issues the invoices
The cleanest arrangement is a single collecting party. The lead organiser sells every ticket, takes every sponsor payment, issues every invoice and receipt in its own name, and pays the event’s suppliers. Buyers deal with one organisation, invoice numbers stay in one sequence, and there is one account to reconcile at the end.
The alternative is for each chamber to collect from its own members and sponsors. That can feel fairer to members, who pay the chamber they know, but it means two sets of invoices and receipts and a harder job adding the figures together afterwards. If you choose this route, agree in advance which chamber collects sponsor money, and what happens when a company belongs to both chambers.
Whichever route you pick, write down which organisation’s name and bank details appear on every registration page and invoice, how refunds are decided and paid, and when the collecting party will pay over any amount owed to the other chamber. Invoicing rules, tax treatment (including whether a co-host’s share counts as income, a reimbursement of costs or something else) and what a receipt must carry differ by country and by type of organisation, so confirm the arrangement with your accountant before you publish a price.
Choose how to split costs and surplus
There are three common ways to share the money of a co-hosted event, compared in the table. Pick one before the event, name it in the agreement, and say what happens if the event loses money. Whichever model you choose, settle the points listed alongside the table as well.
An even split is simple, but it is not automatically fair. If one chamber brings most of the guests and the other does most of the work, say so in the agreement and choose proportions that reflect it.
- Define ‘net’ in one sentence: ticket and sponsor income less venue, food, speakers, printing and payment fees, with a short list of anything excluded.
- Decide whether each chamber’s own staff time and in-kind gifts (a donated room, a sponsor’s wine) count as costs or as contributions, and write down the answer.
- Say what happens to a loss: shared in the same proportions as a surplus, shared up to a stated cap, or carried by the lead organiser. A cap protects the smaller chamber.
- Set a spending ceiling for the lead organiser. Anything above it needs the co-hosts’ written agreement before it is committed.
| Model | How it works | Suits | Watch out for |
|---|---|---|---|
| Percentage of net | After all agreed costs are paid, the net result (surplus or loss) is divided by agreed percentages, for example even shares or shares that reflect each chamber’s contribution. | Events where both chambers bring guests and effort and want to share the risk. | You need an agreed list of what counts as a cost, and nobody knows the final figure until the statement is done. A loss is shared too. |
| Fixed contribution | Each co-host pays or receives a set amount agreed in advance, whatever the final result turns out to be. | Events with a predictable budget, or a partner that wants certainty rather than a share of the outcome. | The lead organiser carries the swing: it keeps any surplus above the fixed amounts and absorbs any shortfall. |
| Cost-only | The chambers share agreed costs and run the event to break even. A small surplus or shortfall is handled by a rule set in advance, such as carrying it to the next joint event. | Community, advocacy or goodwill events where income is not the aim. | Breaking even is a target, not a guarantee. Agree who covers a shortfall. |
Price for two sets of members
Each chamber’s members expect the member rate from their own chamber, and a co-hosted event puts two membership bases in one room. Decide the price structure before registration opens, because changing it afterwards means refunds and awkward emails.
There are three workable structures. Choose the one that matches how different your normal prices are.
- One member rate for every co-host’s members, and a higher guest rate for everyone else. This is the simplest to explain, but you need a way to confirm membership of the other chamber, such as a member code or a list exchanged before registration opens.
- Separate member rates, with each chamber setting its own. This only works when the chambers’ usual prices are similar, otherwise the gap is visible on the same page.
- One price for everyone, with no member discount. This suits a flagship joint event where nobody expects a discount, as long as every invitation says so.
Settle who owns the guest list and what data is shared
A registration list is personal data, and each chamber has made promises about how it handles personal data to its own members and contacts, usually in a privacy notice. A joint event blurs whose promises apply. Decide before registration opens who is responsible for the list and what each party may do with it.
A sensible default is that the chamber collecting registrations holds the list and is responsible for it. It shares with co-hosts only what they need to run the event: names, organisations, dietary needs and access requirements for badges and seating, not phone numbers or full contact histories. Marketing afterwards is a separate question. A co-host should contact attendees about its own services only if they agreed to that when registering, or if they are already its own members or contacts.
Say on the registration page that the event is jointly hosted, name each organisation, and explain in plain words what each will receive. Data protection rules vary by country, and a bilateral chamber may be bound by more than one set, so confirm the wording and the basis for sharing with a legal adviser or the relevant official guidance.
- Who is responsible for the registration list, and who answers a data request from an attendee.
- Which fields each co-host receives, and when: before the event for the door list, and after it for follow-up only where consent was given.
- Whether either chamber may add attendees to its newsletter, and on what basis.
- How long each party keeps the list, who deletes it, and what happens to it if the event is cancelled.
Branding, door staff and settling up
Agree logo order and wording before any artwork is produced. A workable rule is the lead organiser first, co-hosts next in alphabetical order, and supporting partners in a separate, smaller line marked ‘in support of’. Decide whose name leads the event title and the email subject line, who approves artwork, and whether a sponsor’s logo may sit beside the chambers’ logos. Give each party sign-off over its own name and logo, with a short deadline so one slow reply does not hold up the print run.
At the door, staff from both chambers should work from one list, with one job each: someone checking people in, someone greeting and introducing, someone handling walk-ins. Walk-ins who pay on the day belong on the same list and in the same totals. Brief everyone on the price rules beforehand so nobody improvises a discount. Door staff from the partner chamber only need to see names and ticket types, not what each person paid or how the event is performing.
Within an agreed window after the event, the lead organiser sends each co-host a one-page statement. Both sides check it against the agreement, confirm it in writing, and the payment is made. Keep the statement with the invoices in each chamber’s records, and treat the first one as a template: the second joint event will go far faster.
- Income: ticket sales by ticket type, sponsor payments and any other income.
- Costs: each agreed cost line, with a copy of the supplier invoice.
- The net result and the split model applied to it.
- Each party’s share, less anything it has already paid or collected.
- The amount to be paid, by whom, and by what date.
- Headcount: registered, attended and no-shows, so the next joint event can be planned from facts.
Where Chamberflow fits
Chamberflow lets a chamber record partner organisations on an event, each with its role and its share of the event, as a percentage or a fixed amount, so the arrangement agreed in writing also sits on the event record. Each event has a live profit-and-loss view showing projected ticket and sponsor revenue against costs and the projected net. Registration and ticketing run on public event pages that need no login and can be shared by direct link, and dues invoices and event ticket payments sit on one payment ledger, with sequential invoice numbering and receipts that carry the buyer’s tax ID details.
On the day, an event manager, for example a volunteer or a partner organisation’s staff member, can be given a signed, revocable link to the door screen for QR and manual check-in with live attendance, with all money figures hidden from them. Chamberflow records the arrangement; it does not write the agreement, set the split, advise on tax or data sharing, or negotiate between chambers. Those decisions stay with each chamber’s staff and board and their advisers.