In December, we had the pleasure of co-hosting a webinar, “Modernizing Family Office Finance,” with our technology partner, BILL, and our client, Mariner Ultra.
Joined by Alex Brown and Phil Boscarino from the Mariner Ultra team and Andrew Thomas from BILL, we sat down to talk about how using SumIt and BILL software in combination has made a huge difference in Mariner’s operations. We shared what was painful before, what’s changing in the market, and what “modernization” actually looks like in day-to-day family office operations.
Below, you’ll find a recap of the main points from our webinar. If you’d like to watch the recording, you can access it at the link here — and we thank you greatly if you joined live!
1. The “before”: manual work didn’t scale
Mariner described a familiar reality for many family offices around the country — as their outsourced family office practice grew, multi-entity complexity quickly turned into bottlenecks.
With larger clients — i.e., those with 50 to 100+ entities — reporting became extremely difficult in their prior accounting setup. With that, bill pay was highly manual. Approving and paying bills entity-by-entity simply wasn’t sustainable, especially if they wanted to grow the firm further.
The underlying problem was not a lack of effort — in fact, it was a mismatch. When your workflows and tech stack aren’t built for multi-entity structures, teams end up rebuilding the same process in spreadsheets and workarounds, and those processes are highly breakable and error-prone.
2. Family office finance is not corporate finance
One of the biggest themes we shared was also how different family office accounting is from corporate accounting. This is exactly why we built SumIt, and we emphasize that all the time.
Essentially, in corporate environments, requirements tend to be more standardized and compliance-driven. In family offices, the work is “for the needs of the family,” and those needs vary widely. They depend on family members, estate structures, and what the family actually wants to see.
That variability changes everything. So, teams need flexibility — not only in how they manage entities, but in how they produce reporting that’s actually useful. Alex from the Mariner team put it well: families may not want a long, traditional P&L. They may actually want a simple one-page view that highlights what they care about, and that can differ client to client.
I also shared that even standard reporting conventions don’t always translate cleanly. For example, a traditional cash flow statement starting with net income often doesn’t resonate in a family context. That’s why we talked about presenting cash flow as sources and uses of cash.
3. The market is shifting: more demand, higher expectations, less patience
Broader forces are shaping the space. There’s significant wealth being created and inherited, which is pouring gasoline on the growth fire of multi-family offices.
At the same time, clients are increasingly demanding. They want better access to information, faster reporting, and technology-enabled processes they can interact with, much like what they’re used to in technologies they use in their personal lives.
Phil also emphasized that bill pay and reporting are foundational. You have to do them, and you have to do them right. But if those fundamentals take too long, they block the team from delivering the real value clients and advisors care about.
With shifting expectations also come changes for software providers. Teams can’t wait six months to onboard anymore, especially with ongoing talent constraints and the operational risk of long implementations.
4. Mariner Ultra’s tech stack and best-in-breed partnerships
A key decision point Mariner shared when evaluating what software to use for their operations was whether to choose an all-in-one solution or build a stack with strong partners. Their philosophy was to find the best partners.
They emphasized two criteria in particular:
Do the vendors know the family office space and keep investing in it?
Do the relationships feel mutual, collaborative, and responsive?
Both Phil and Alex from Mariner Ultra noted that large corporate accounting platforms can be expensive, complicated, and overloaded. On top of that, they’re seldom ever tailored to family office needs.
On the other end of the spectrum, smaller tools often can’t handle complex reporting. The team wanted something flexible enough to support real-world customization and scalable enough to handle large multi-entity clients.
5. Integration mattered (especially for inter-entity work)
During the webinar, we spoke directly about why the BILL + SumIt integration mattered so much to Mariner. In this space, inter-entity activity is constant. Paying bills across entities, splitting expenses, and handling due-to/due-from activity creates complexity that becomes painful when systems don’t connect easily.
Mariner emphasized they want specialized systems that talk to each other, rather than forcing everything into one tool. The team framed this as the future — one that combines more data sources and workflows, and demonstrates a stronger need for interoperability.
6. Where the efficiency gains showed up
Mariner pointed to time saved in the places that used to consume the most effort:
Less manual work processing bills across many entities
Reduced reconciliation effort through better standardization and unified structure
Faster reporting that could be generated at the click of a button, even across many entities
Phil made the point I keep coming back to: if you spend hours reconciling and processing bills, does the client value that time? Or would they rather you spend time delivering insights and proactive support? Good question.
He shared a simple example about noticing a water bill that was 6–7x higher than normal. He reached out about it and discovered a leak at the client’s pool in Mammoth. The amount itself wasn’t huge, but the client’s reaction was — because this was tangible value.
7. Looking ahead: more complexity, practical AI
As we talked about our thoughts on the future, two trends seemed most prominent.
Investment structures are getting more complex, including partnership-style investments and multi-layer ownership that require a better “look-through” understanding
AI will become baseline, but the useful version is practical and controlled
Alex Brown described being “excited but skeptical,” and I agree with that framing. AI is most valuable when it acts like an extension of the team with clear oversight — especially for workflows like reconciliation and onboarding tasks.
In our experience at SumIt, we’ve seen that onboarding is one of the biggest deterrents to switching software. So, we’ve invested in our own onboarding application because AI can meaningfully speed up structured migration steps (when the data is clean and there are controls in place). In some cases, what used to take months can now take days.
Closing thoughts
The two biggest pieces of advice I shared on the webinar still stand:
First, be willing to share openly with software providers. Fit and value become easier to identify.
Second, don’t evaluate software in isolation. Evaluate the team behind it, because this space depends on trust, responsiveness, and long-term partnership, and your software choices should too.
To watch the full webinar, access the recording here:
https://www.bill.com/events/modernizing-family-office-finance
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