Rethinking B2B Payments: Maex Ament on Causa Prima’s Agent-to-Agent Network
After 25 years building accounts payable businesses, Maex Ament sees the same unresolved problem: software can improve processes within a company, but the back-and-forth between buyers and suppliers still depends on people chasing emails, approvals, and payments. His sixth company, Causa Prima, aims to close that gap with a network of AI agents that coordinate directly, while finance teams set the rules and retain control.
In this interview with Eqvista, Ament, CEO and co-founder of Causa Prima, reflects on his journey from SAP to building Taulia and explains why he believes agent-to-agent collaboration is the next step for B2B finance. He discusses overlooked opportunities in payment timing and early-payment discounts, the importance of earning CFOs’ trust, and how Causa Prima’s $10 million pre-seed round will support its growth. For founders tackling complex financial workflows, his message is clear: understand the problem deeply, lead with the customer’s needs, and never let clever technology come at the expense of careful handling of money.

Maex, could you begin by sharing a brief overview of your background and the path that led you to co-found Causa Prima?
I grew up wanting to build video games. Instead, I’ve spent 25 years in accounts payable. I started at SAP like every good German developer, building on their AP module, then left in 2000 to build my first startup. I bootstrapped it because I didn’t know venture capital existed. Automated invoicing software,600+ clients including Apple, Intel, Siemens, and Aldi. I sold it in 2005 and then raised $250M to build Taulia, where we invented dynamic discounting and moved $50 billion a year across five million suppliers before SAP acquired it. After that: Centrifuge, a frontier-tech fund and 150+ angel investments.
Causa Prima is my sixth company, and I’m still solving the same problem I started with. Every tool I ever built hit the same wall: the moment the other company needed to be involved, the software stopped and a human picked up the phone. The real problem was never inside one company, it’s in the hand-off between two. So with Henrik Gebbing, who built Finoa into a €10B institutional fintech, and Philip Stanislaus, who ran 600+ enterprise security audits at Oak Security, we’re finally building for that space.
How would you describe Causa Prima to someone who understands finance operations but not AI?
Forget AI for a second. Think about where B2B actually breaks. Every payment depends on two people reaching each other at the right time and coming to an agreement. Emails get lost. Calls get missed. The approval is stuck in Dave’s inbox, and Dave is at a conference in Vegas, not checking his inbox.
Causa Prima puts buyers and suppliers on the same network and gives each side a digital worker that handles the back-and-forth directly. A dispute that used to take three weeks of email ping-pong resolves in seconds, because there’s no inbox in the middle. Your team sets the rules and keeps control of every decision that matters. The system does the chasing.
Getting paid becomes the simplest part of doing business again, instead of the part that quietly eats the most time. And most importantly, just because an invoice says “NET30” doesn’t mean this is the best outcome for both parties – so our agents optimize the timing of the payment making it a true win-win.
What problem in B2B finance are you most determined to solve, and why is now the right time to build an agent-to-agent network for AP and AR?
The chase. Most businesses spend more time chasing money than making it. The industry keeps shipping the same answer: AP tools for buyers, AR tools for suppliers, dashboards for everyone. All of it optimizes one side of the table. The delays, disputes, and missed terms fall off the edge of every tool ever built and into someone’s inbox. No one-sided tool can fix that, because the other company isn’t on the system.
Why now? Agent-to-agent is the first architecture that can actually solve this. Agent-to-human Doesn’t work. You’ve automated one side, but the other side is still on vacation, still done at 5pm. And the timing pressure is real: AI is making business denser, not simpler. More suppliers, more partners, more payments per hour than any team was built to handle. The winners won’t be the ones with better dashboards. They’ll be the ones running on a system where the back-and-forth resolves itself.
Which pain points are most overlooked in today’s finance workflows, and where do you see the biggest inefficiencies: invoicing, disputes, discounts, or payment timing?
The most overlooked thing is the long tail. Every AP team has a threshold for which payments are worth chasing (usually only 20% of invoices make the cut). Why would a human negotiate a 3-cent discount on a $3 invoice? The call costs more than the invoice. An agent doesn’t have a threshold. If there’s a percent to be saved on a $0.10 invoice, it goes after it the same way it goes after the $1M invoice. That untouched 80% is where the opportunity hides.
As for ranking: disputes are the most painful, because a $200 disagreement can block a $200,000 invoice for weeks. Discounts are the most invisible; I invented dynamic discounting over a decade ago, and the early-payment value still going uncaptured is staggering. And payment timing is the most outdated.
Terms get locked into a framework contract once a year and left alone, even when the business looks completely different than when it was signed. And most importantly: just because an invoice says net-30 doesn’t mean that’s the best outcome for either side. Net-30 should have been left in medieval times.
How do companies get started with your product without having to change too much of their current setup or workflow?
This was a design principle from day one.I’ve lived through enough enterprise rollouts to know that “first, replace your ERP” is where good ideas go to die. Causa Prima sits alongside what companies already run. No new tool to learn, no migration, no big-bang rollout: the agents plug into existing processes and start taking the chase off people’s plates from the first week. And because it’s a network,it compounds. Every company that joins makes it work better for everyone already on it.
What are the main reasons companies hesitate to adopt something like this, especially when it involves both technology and finance processes?
I hear the same thing in every conversation: “I have a personal relationship with this partner. I’m not comfortable letting an agent negotiate on my behalf”. Totally valid. CFOs aren’t afraid of agent-to-agent negotiation but are afraid of signing off on something they can’t explain to their board. So we made it explainable. The CFO sets the guardrails: minimum acceptable terms, maximum discount,no negotiations on payroll day. The agent never crosses those lines. You start with the long tail, not your
strategic partners (less at stake, less emotion) and let the agent prove itself. And you don’t go fully autonomous on day one: the agent proposes, you approve. Trust is engineered, not promised. Philip ran 600+ security audits before we built this, and that DNA runs through the product.

How do you bring both buyers and suppliers into the same system, and what makes that better than each side working separately?
It usually starts with the buyer: an enterprise joins and brings its supply chain onto the network. That invitation is easy to accept, because joining doesn’t mean ripping anything out. Instead it means your side of the back-and-forth gets handled too. Each side gets real value on its own, and every new company makes the network better for everyone already on it.
Why is that better than working separately? Picture a supplier who’s worked with a big retailer for years.They’re owed $10K, due in 60 days, but payroll hits Friday. Do they pick up the phone and ask for it early? Most people won’t, it feels awkward. An agent doesn’t have that problem. It knows payroll is due, knows the 1% discount makes sense, makes the ask, and the retailer’s agent evaluates it on the spot.
That negotiation literally cannot happen when each side sits on its own disconnected tool. One-sided optimization has a ceiling. A network doesn’t.
What results do customers usually notice first after using the product, and what do they say improves most?
The first thing people notice is silence, but in the best sense. The reminder emails stop being written. Disputes that used to sit open for weeks come back resolved in seconds. What improves most is what teams do with the hours they get back. A benchmark that should shock more people: the best AP teams run 3.3 people per $1B in revenue. The worst run was 14.4. Same company size, 4x the headcount, and the difference was never the people. It’s whether they’re stuck matching invoices, or deciding which suppliers to pay early and managing cash. We move teams toward the first group. And my favorite signal isn’t a metric: the week after launch, a floor roofer, a freight broker in Ohio, and a cleaning company in Spain all signed up writing “I want to end the chase for my payments.” Our own words, used right back at us.
Congratulations on the recent $10 million pre-seed round. Could you share what this milestone means for Causa Prima at this stage? What were the most important factors that helped you close the round?
Thank you. The round was led by Creandum, with Kfund, HelloWorld, and Angel Invest, plus 50+ founders and executives from companies like Qonto, Pennylane, SAP, ING, SoFi, LIDL, and Google DeepMind — the largest pre-seed ever raised by a company in Spain. What it means practically: networks reward speed, and this lets us build at the pace the opportunity demands, on both sides of the
market. What closed it? We agreed on the Creandum term sheet relatively quickly, without a formal pitch deck. We showed a Lovable animation instead, a fictional timeline of headlines from 2026 to 2033 and our plan to get there. But honestly, the deck didn’t matter because the ingredients did. Between the three of us, we’ve built ten companies, raised $400M, and spent 25 years on the only thing that actually matters in business: getting paid. Investors weren’t betting on a thesis. They were betting on people who’ve already been paid to learn these lessons, showing up with a live product and a shared conviction that agent-to-agent commerce is a fundamental shift. And whoever builds the trusted financial layer for it builds something that lasts decades.
What advice would you give to founders trying to solve a complex operational problem in finance?
Earn the right to solve it. Finance is a domain where trust is the product, and trust doesn’t come from a pitch deck but from scar tissue. You don’t need 25 years’ experience, but you do need to understand the problem better than the people living it. My favorite test: when your customers use your own phrase back at you, you named the right problem. Nobody wakes up thinking “I have a chase problem”. They wake up behind on payroll, with a client who hasn’t answered in two weeks.
And don’t lead with the technology. The AI is the mechanism, not the pitch. Solve the actual problem and be relentlessly precise about how you handle it while you do. In finance, the product can be clever, but the handling of money never gets to be sloppy.
