The operating system for SMB finance: Why we’re leading Affiniti’s Series A

Operating a small business today is tougher than ever.

SMBs operate on thin ice. 22% of U.S. small businesses struggle to pay bills, and 72% have less than four months of cash reserves. Margins are vanishing, inflation is a moving target, and rising uncertainty around tariffs is causing industries like HVAC, pharmacies, and medical clinics to drown in rising costs and shrinking reimbursements, all while still grappling with spreadsheets and paper invoices.

The core issue is cash flow—not just how little there is, but how hard it is to predict. Many of these SMBs are flying blind, with no real-time visibility into when cash is coming in or going out. Collections are unpredictable, especially for businesses dependent on insurance reimbursements or net 60 vendor terms. Meanwhile, input costs change week to week. When owners miss the mark on forecasting, they get hit with overdraft fees or take on high-interest loans, further squeezing already razor-thin margins. It’s a vicious cycle that punishes operators twice - once when the cash runs short, and again when those loans eat into whatever margin is left.

While startups and enterprises have a full stack of modern financial tools, many traditional small and medium-sized businesses (SMBs) still lack basic systems for spend management, bill pay, and forecasting. There’s no finance team, no off-the-shelf solution that fits their workflows, and often, no software at all.

‎Affiniti is flipping the script. They started with a smart wedge, a co-branded business credit card, and expanded into a full-stack financial platform for the underserved backbone of the economy, like the laundromat owner in Ohio or the podiatrist in Georgia, who are still juggling analog workflows, fragmented payments, and insurance and vendor chaos. 

We're excited to lead Affiniti's $17 million Series A because we recognize the critical need to serve America’s sprawling SMB base with modern fintech solutions.

With the rise of the digital economy, private equity consolidation, and inflationary pressures, it's extraordinarily difficult to operate a business. A decade into modern fintech, Main Street businesses are still guessing when it comes to finances. SignalFire shares our conviction that it’s time for a change, and they’re helping us create this new market together.

Aaron Bai

Co-Founder & CEO, Affiniti

How it started: A unique wedge to reach underserved SMBs

Affiniti didn’t begin with a broad platform or buzzword-driven vision. The team started by talking to operators - pharmacists, HVAC contractors, podiatrists - and asking what actually needed fixing. The answer was surprisingly consistent: paying vendors, managing receipts, and understanding cash flow were all painful, fragmented, and high stakes.

The company’s first product is a business credit card, co-branded with trade associations that SMBs already trust. By white-labeling its platform and distributing through those partners, Affiniti built trust quickly in markets where fintech adoption is historically low. With nearly 10x revenue growth in the past year and early SaaS traction, it's clear the wedge is working.

Even more telling: for most of their customers, Affiniti is the first fintech solution they’ve ever used to manage their business.

Where it's going: Building the financial OS for America’s Main Street

The credit card gives Affiniti a critical beachhead: visibility into spend. From there, they’re layering in the workflows that SMBs typically manage across dozens of tools, or not at all.

They’ve launched an expense management product that gives owners control and oversight without needing a finance team. Next comes bill pay and business checking, both designed around how these businesses actually operate. For instance, many pharmacy customers buy generics with credit but pay for branded drugs via ACH. Affiniti can support both seamlessly.

With deeper integrations—think ERP and POS systems—they’ll unlock vertical-specific insights, whether that’s managing reimbursements in healthcare or inventory cycles in HVAC. Over time, all of this feeds into the bigger vision: a financial command center that helps SMBs not just react but plan. Forecasting, margin analysis, and cash flow modeling are all packaged in a product that SMBs can actually use.

Built-in credibility: Affiniti embeds with the institutions SMBs already rely on

Affiniti’s distribution strategy is purpose-built for its customer base. The company partners with the most trusted trade associations in industries like independent pharmacy, HVAC, podiatry, property management, automobile dealerships, and prosthetics. These aren’t marketing channels - they are respected institutions with deep relationships across their member base.

Affiniti fully white-labels its platform under each association’s brand and co-markets it through newsletters, member portals, and in-person events. The result is more than credibility; it's a glowing endorsement. Business owners see Affiniti as a tool built specifically for them, not another one-size-fits-all fintech product.

We built Affiniti to meet SMBs where they already are—within the communities and associations they trust. These aren’t just distribution channels, but sources of credibility in long-overlooked industries. When your first customers come from listening, not ads, you quickly learn what truly matters—and that’s what makes our product resonate.

Sahil Phadnis

Co-Founder & President, Affiniti

These SMBs haven’t adopted modern fintech tools not because they’re resistant to software, but because no solution has ever truly fit their needs. Most products are designed for tech-forward businesses with dedicated finance teams and clean digital workflows - a far cry from the realities of a podiatrist’s office or an HVAC shop. That’s why Affiniti’s GTM motion isn’t just smart, it’s necessary. Distribution through trusted associations only works when the product behind it is purpose-built for how these businesses actually operate.

This motion accelerates adoption and reaches the right customer: high-FICO, multi-decade operators who may never click a Facebook ad but will pick up the phone for their association.

From cold calls to category creation: A founding team at the frontlines

Aaron Bai and Sahil Phadnis dropped out of UC Berkeley at just 16 and 18, not to chase headlines, but to build Affiniti from the ground up. For the past two years, they’ve been pounding the pavement—walking into pharmacies, HVAC shops, and specialty clinics to understand how these essential businesses really work, what slows them down, and what no one else is building for them. Before writing a single line of code, they were face-to-face with owners, listening more than pitching, earning trust the old-fashioned way.

What struck us first about Aaron and Sahil: real customer empathy that shows up in everything they build—from purpose-built fintech solutions to a trust-driven GTM that meets SMBs where they are. It’s a rare mix—and why we’re excited to back Affiniti.

Jonathan Lim

Partner, SignalFire

That grit and humility are baked into Affiniti’s DNA. It’s how they signed their first 1,000 customers with almost zero marketing. It’s why retention is through the roof, and it’s why Affiniti isn’t just another fintech - they’re becoming the financial backbone for America’s most overlooked operators. And they’re just getting started.

The SignalFire advantage: AI-driven, expert-led, founder-focused

We’re incredibly excited to partner with Affiniti and collaborate on several key initiatives. Our team of go-to-market experts, led by the former CMO of Stripe, Jim Stoneham, helps Affiniti reach target customers identified by our in-house data science team. Plus, our People & Talent experts, led by the former head of people at Webflow, Heather Doshay, use our Beacon AI talent engine to help Affiniti hire the best engineers. 

Affiniti is building what most fintechs missed - real financial infrastructure for the real economy. In industries long ignored by tech, they’ve earned trust by listening, building with care, and meeting customers where they are. Their vertical-first, distribution-savvy model is powering rural pharmacies, local clinics, and family-run businesses across America. These are the builders behind our economy - and the reason we’re proud to back Affiniti.