Proof, not promises.
Most firms hand you a deck. We hand you the system we trust to run our own regulated lender. MARCUS is the AI back office we built for B:Side Capital. Proven on our own operation, with our own name on the line, before we offered a version of it to anyone else.
I didn’t start Main & Machine to sell AI. I built MARCUS to run my own company: B:Side Capital, a regulated SBA and CDFI lender, where a wrong call has real consequences. I made every mistake on my own operation first, with my own money and my own name on the line. Only once I trusted it with the thing I’m accountable for did I take it to anyone else. We sell exactly one thing: what we already proved on ourselves.
Christopher Myers · Founder & Chairman, Main & Machine · CEO, B:Side Capital
We didn’t sell it until we trusted it with our own loans.
The clearest case study we have is our own. Our founder runs B:Side Capital; MARCUS is the AI back office we built to run it, under real regulatory stakes, on our own infrastructure. That it’s our own company isn’t a caveat. It’s the credibility.
Prep ate the days.
B:Side Capital is a regulated SBA 504 and CDFI lender. Before anyone decides anything, someone gathers the documents, pulls the reports, and drafts the paperwork. The same steps, over and over, across seven departments. The team needed a controlled boundary around borrower documents and a record of how the system used them.
Fourteen agents, in-house.
We read roughly 840 of B:Side’s own process documents and built fourteen AI agents across seven departments. Borrower documents are processed locally; selected tasks can use external reasoning on filtered text. The system prepares work against B:Side’s procedures, with human approval for consequential actions.
A person signs off. Always.
MARCUS does the gathering, checking, and drafting, then hands finished work to a person who says yes, sends it back, or escalates. It clears the routine and drafts the hard calls. The judgment stays with the people accountable for it.
MARCUS: a private AI back office for a regulated lender
The brief was one line: take the prep off our people’s plate, without ever taking them out of control. Walk the whole build: the seven departments, the fourteen agents, and the four surfaces the team already uses.
Read the full teardown →Client work goes up the same way: verified, and signed off.
MARCUS we can open up because it’s ours. Everyone else’s work goes on this shelf by one rule: we publish a client story only when the numbers are verified and the client signs off in writing. No borrowed logos, no rounded-up results, nothing here we can’t stand behind. Here is what the first one measured:
Estimated staff preparation hours returned during June–August 2026, calculated from B:Side’s initial workflow studies. This is operating capacity, not measured payroll savings.
Reported weekly use by week six, across a staff of 45 employees. The percentage is rounded; an exact active-user count is not published.
Borrower identifiers reported as sent to outside models during the measurement window. Filtering is required; detection is not guaranteed to be perfect.
Of consequential actions approved by a person during the reported window, before sending, filing, posting, or paying.
What might work in your operation? Describe one recurring task and get a free written first step. Your plan names what to investigate before deciding whether a build makes sense.
The guarantee: If a scoped workflow is not live in your operation within 90 days, we keep building at no charge until it is.
The credit: Your audit fee can be credited toward a sprint signed within 60 days, up to 25% of the sprint price.
We reply within 24 hours. A fixed quote follows an agreed scope, before paid work begins.
— Christopher Myers, Founder