← Embedded Finance Index 2026

Stax

“Can a flat-rate SMB payment processor evolve into the full financial operating system for small businesses and ISVs by stacking lending, billing, and embedded payments on top of its payment rails?”

Founded2014
HQOrlando, FL, United States
FoundersSuneera Madhani, Sal Rehmetullah
Total raised$245M
Latest roundSeries D (Debt most recent per PitchBook)
Valuation$1.1B+ (at founders' exit)
IndustryFintech / SMB banking

The story

Founded in 2014 as Fattmerchant with a disruptive flat-rate/interchange-plus subscription model for SMB payment processing, the company rebranded to Stax in 2021 and expanded from pure payment processing into a full integrated payments platform. Stax layered on embedded payments for ISVs (Stax Connect), billing/invoicing (Stax Bill with Avalara tax automation), and SMB lending (Stax Lending/Capital), positioning itself as an all-in-one financial OS for SMBs and software platforms. The original sibling founders exited circa 2023–2024 as the company crossed $1.1B valuation; new leadership is executing a go-to-market and technology realignment in 2026.

Last 12 months

2026-03

Stax Payments announced C-suite revamp, naming Andrew Monroe as Chief Commercial Officer (from Bluefin), promoting a new CTO, expanding COO remit, and creating a Chief AI Officer role.

2025-03

Founders Suneera Madhani and Sal Rehmetullah confirmed they exited Stax Payments and launched a new fintech, Worth, with a $20M seed round. Stax was valued at $1.1B+ at exit with $245M raised.

Product timeline

2014

Founded as Fattmerchant in Orlando, FL, offering a flat-rate subscription-based payment processing model for SMBs.· pivot

2021

Rebranded from Fattmerchant to Stax Payments, unifying its brand around integrated payment technology.· pivot

2022

Launched Stax Connect, an embedded payments platform for ISVs and software platforms.· banking

2023

Launched Stax Lending (capital/lending product) and Stax Bill (billing/invoicing), expanding beyond payment processing into embedded financial services.· lending

2025

Founders Suneera Madhani and Sal Rehmetullah exited Stax after nearly 10 years; company valued at north of $1.1B with $140M+ in recurring revenue.· pivot

2026

C-suite revamp: new CCO Andrew Monroe (from Bluefin), new CTO, COO, and chief AI officer appointed.· pivot

The stack

2 layers disclosed in Stax’s embedded-finance stack

Payments / PSP

Stax Payments (self-operated)Stax Connect (self-operated)

Lending

in the full report

Accounting gap: none

4 more providers across 1 layer, with confidence-scored evidence and source URLs, are in the Embedded Finance Index report.