Gusto

Sierra

Gusto

Gusto charges a monthly base fee plus a per-employee fee. The Simple plan starts at $40/month plus $6 per employee per month.

Plus and Premium tiers add features like time tracking, PTO management, and dedicated support at higher price points.

The per-employee pricing creates natural revenue growth — as customers hire more people, Gusto makes more money without any additional sales effort. This aligns Gusto's success with their customers' growth, which is a beautiful incentive structure.

Additional revenue comes from embedded financial products. Gusto Wallet (employee banking), Gusto-run health benefits, 401(k) administration, and workers' comp insurance all generate fees.

The payroll platform becomes a distribution channel for financial services — once you process payroll for a company, you have a direct relationship with every employee and can offer them financial products.

Sierra

Companies pay Sierra to run their customer service with AI agents instead of hiring rooms full of humans. The agent talks to your customers over chat.

It answers questions. It processes returns.

It updates subscriptions. Here is the clever part.

Sierra charges based on outcomes, not seats. Brands pay when the AI actually resolves a problem, not just for having the software installed.

That pricing is unusual. Most software charges a flat monthly fee no matter what.

Sierra only gets paid when the bot does the job.

Gusto

Josh Reeves, Edward Kim, and Tomer London were Stanford engineering graduates who noticed that every small business owner they talked to hated the same thing: payroll. Running payroll meant calculating federal, state, and local taxes, filing quarterly returns, issuing W-2s, managing direct deposits, and dealing with an alphabet soup of compliance requirements (FICA, FUTA, SUTA).

One mistake and the IRS sends a penalty notice.

The existing solutions were terrible for small businesses. ADP and Paychex dominated the market but were designed for mid-to-large companies.

Their interfaces looked like they were built in 1998 (because they were). Their pricing was opaque.

Their customer service required calling a 1-800 number and sitting on hold. Small businesses with 5-50 employees were dramatically underserved.

The trio founded ZenPayroll in 2011 (rebranded to Gusto in 2015) with the mission of making payroll dead simple. The first version was a clean web interface that let business owners run payroll in a few clicks — enter hours, review the numbers, hit submit.

Gusto calculated all taxes automatically, filed them with the government, and sent direct deposits. What used to take half a day took five minutes.

Sierra

Bret Taylor had already done the impossible twice. He co-created Google Maps.

He later became co-CEO of Salesforce, chaired Twitter's board during the messy Elon Musk takeover, and became chairman of OpenAI in late 2023. Clay Bavor spent 18 years at Google, most recently running its Labs group.

The two friends left their big jobs in 2023 to build something together. They picked customer service on purpose.

It is the least glamorous corner of software. Their logic was simple.

Companies hate their support costs. Customers hate waiting on hold.

AI that actually resolves problems could fix both sides at once. They launched Sierra in February 2024 with $110 million from Sequoia and Benchmark.

Gusto

Gusto grew by being the payroll platform that accountants recommended. Accountants manage payroll for thousands of small businesses, and Gusto built a dedicated Partner Program for accounting firms.

When a CPA recommends Gusto to all their small business clients, that's efficient distribution at scale.

The product-led growth motion is strong. Gusto's clean design and simple setup meant small business owners could sign up, enter their employee information, and run their first payroll without talking to a salesperson.

Free trials converted at high rates because the alternative was going back to manual calculations.

Expanding from payroll into HR, benefits, and financial services followed the natural workflow. Once Gusto ran payroll, adding benefits administration was a natural upsell — the same system that calculates pre-tax deductions can also manage the benefits that create those deductions.

Sierra

Sierra went straight for big brands, not tiny startups. SoFi, Ramp, ADT, Sonos and Brex signed up early.

By 2026 it said more than 40% of the Fortune 50 were customers. The trick was trust.

Enterprises are terrified of an AI bot going rogue and insulting a customer. So Sierra built guardrails and let each company control exactly how the agent behaves.

Bret Taylor's contacts did the rest. When the chairman of OpenAI calls a Fortune 500 CEO, they pick up.

Sierra hit $100 million in annual recurring revenue in November 2025, seven quarters after launch, and $150 million by February 2026. In April 2026 it launched Ghostwriter, which builds and deploys a new agent from a plain-English description.

Gusto

ADP and Paychex aren't going to cede the small business market quietly. ADP Run is their small business product, and they've been modernizing it aggressively.

ADP has 70+ years of trust, massive sales teams, and relationships with every accountant in America. Gusto has a better product experience, but ADP has distribution that's hard to match.

Rippling is the most dangerous competitor. Parker Conrad (Rippling's CEO) is building an "all-in-one" HR/IT/Finance platform that includes payroll alongside device management, app provisioning, and expense management.

Rippling argues that payroll should be one feature in a broader system, not a standalone product. If companies buy Rippling for IT management and get payroll included, Gusto loses the deal.

Moving upmarket is hard. Gusto's sweet spot is companies with 1-100 employees.

Larger companies have more complex needs — multiple pay schedules, union rules, multi-state compliance, custom integrations — that Gusto's platform historically hasn't handled as well as incumbents.

Sierra

Everyone is building AI customer service agents right now. Decagon has raised at a multi-billion valuation.

Salesforce, ServiceNow and Intercom all shipped their own agents. Sierra is not the cheap option.

It sells premium AI to giant companies that move slowly. The bigger risk sits underneath the product.

Sierra does not make its own AI models. It rents them from providers like OpenAI and Anthropic.

If those model makers decide to compete directly, Sierra's edge gets thin fast, and its co-founder chairing one of them only makes that question louder. A $15.8 billion valuation on roughly $150 million in revenue leaves almost no room for a stumble.

Gusto

Gusto Payroll — automated full-service payroll processing with tax calculations, filings, and direct deposits across all 50 states. Gusto Benefits — health insurance, dental, vision, 401(k), HSA, FSA, commuter benefits, and workers' compensation administered through the platform.

Gusto HR — hiring and onboarding tools, employee self-service portal, org charts, and document management. Gusto Time & Attendance — built-in time tracking with PTO management, holiday calendars, and overtime calculations.

Gusto Wallet — a free employee financial wellness app offering early wage access, savings accounts, and financial planning tools.

Sierra

The core product is the Sierra AI agent. It is a branded customer service bot that companies deploy on their website, app, and phone lines.

It handles the boring stuff. Order tracking.

Refunds. Password resets.

Account changes. Sierra also built its own tools to test and monitor these agents so they do not make things up.

In 2024 the company added a voice version that talks to customers on the phone. In April 2026 it added Ghostwriter, a tool that builds and deploys a new agent from a plain-English description.

The whole pitch is one AI agent that carries your brand's name and never sleeps.

Gusto

Google Capital (now CapitalG) led the Series C. General Catalyst invested early and has been in multiple rounds.

Dragoneer, T. Rowe Price, and Fidelity participated in later growth rounds.

Y Combinator was the starting point (Winter 2012 batch). The company was valued at $9.5 billion in its latest funding round in 2022.

Sierra

Sequoia Capital and Benchmark wrote the first checks at launch in February 2024, $110 million between them. Greenoaks Capital then led both the $175 million round in 2024 and the $350 million round in September 2025.

In May 2026 Tiger Global and Google's GV led a $950 million round at a $15.8 billion valuation, with Benchmark, Sequoia and Greenoaks back in. That takes total funding to about $1.6 billion.

That is partly the product and partly Bret Taylor. Investors bet on founders who have already built billion-dollar things.