How Do I Add Another Company to My ADP Account? (w/Examples) + FAQs

You cannot add a second company to ADP yourself. Only ADP can create and link a new company. RUN Powered by ADP treats every business as its own payroll and tax entity, not a setting you toggle inside your account.

This catches growing owners off guard the moment they open a second LLC, a new location, or a client entity. ADP itself reports over 900,000 small-business clients on its RUN platform as of 2026. Many of them eventually manage more than one company. The feature that solves this, Multi-Company Access, has to be turned on by ADP first.

Why ADP Doesn't Have a Self-Service "Add Company" Button

ADP builds RUN Powered by ADP around the legal entity, not the login screen. Every company gets its own IID, short for interactive identification number. ADP uses this code to tie one business's payroll, tax filings, and billing together, and no two companies ever share one.

Adding an employee only touches one company's records, so ADP lets you handle that yourself. In the RUN Powered by ADP web app, you open the Employees menu and click Add Employee or Add Contractor. The change applies right away, with no wait for ADP's help.

Linking a whole new company is a bigger change. It touches payroll tax sign-ups, direct-deposit banking, and a separate billing account, not one table of employee records. ADP has to set that up on its side before your login can reach it. Think of it like a new ADP client getting onboarded before its first payroll run.

Many owners assume the option is buried in a settings menu somewhere. They lose an afternoon clicking through tabs that were never going to hold it. The dependable fix is simpler: call or message your ADP rep or the support line. Ask them to add the new company and issue it a fresh IID.

A common misconception treats payroll software like a spreadsheet. People picture a new business getting a new tab, similar to adding a new sheet to a workbook. Payroll platforms cannot work that loosely. Each company files its own federal and state tax returns under its own EIN, and merging two businesses under one filing would corrupt both.

Gusto and QuickBooks Payroll follow the same entity-first model, so this limit is not unique to ADP. Every serious payroll platform treats a new company as a new client relationship. Once ADP finishes the setup, you never repeat it. The link between your login and the new IID stays in place from then on.

How Multi-Company Access Works Once ADP Turns It On

Multi-Company Access, often shortened to MCA, is the feature that lets one ADP login reach several companies. ADP builds it so you never need separate usernames for each business you run. Once ADP sets up MCA for your account, logging in shows a Select Company screen instead of one company's Welcome page.

That screen lists every company tied to your credentials, by name and IID. You tap the one you want to work in for that session. From there, you land on that company's own Welcome screen.

Its employees, payroll runs, and reports stay fully separate from any other company on your login. ADP's own product notes describe this exact flow in its Multi-Company Access notes, and the setup has carried forward since ADP introduced it. You can always confirm which business you're in by checking the company name and IID shown near the top of the screen.

Switching companies mid-session does not require logging out and back in. Look for an arrow or a company switcher near the company name and IID at the top of the screen. Tapping it reopens the Select Company list, so you can jump to a different entity in a few taps.

This switcher works from several key screens, not only the login page. That matters because many people forget to check which company they are in before running a payroll or pulling a report. A quick glance at the IID on screen confirms you are in the right one.

The practical value shows up the first time you manage two payrolls back to back. Instead of logging out of one ADP account and into a different one, you stay signed in and switch in a few taps. This is not the same as merging two businesses into one payroll, since each keeps its own tax filings, its own employee list, and its own bill. MCA only cuts down how many logins you need to reach all of them.

Which Situation Applies to You?

The right next step depends less on the software and more on why you're adding a company. A single owner opening a second LLC needs a different conversation with ADP than an accounting firm managing a dozen clients. A franchise adding its fourth location has different volume concerns than either one. Sorting yourself into one of these groups tells you who to call and what to ask for.

The Single-Entity Owner Opening a Second LLC

If you already run one company on ADP and recently formed a second legal entity, your task is the most direct one. Call your ADP representative or the support line. Ask them to add the new company under your existing login, using Multi-Company Access. Say plainly that you want both companies reachable from one set of credentials, not two separate accounts.

You will need the new company's EIN, its state tax registration, and basic banking details before ADP can finish the setup. Expect a short onboarding call similar to opening your first ADP account. Payroll tax registration for a brand-new entity cannot be skipped or copied from the first one. Each business owes its own filings under its own EIN.

The Bookkeeper or Accounting Firm With Multiple Clients

Accounting firms and bookkeepers who manage payroll for several unrelated clients usually need a different tool. ADP's Accountant Connect platform fits better than Multi-Company Access on one owner's login. It is built for firms that view and manage several clients' payroll without becoming the account owner for each one. That distinction matters because ownership carries billing and liability.

You refer a client, and ADP's team reaches out to set up that client's own ADP account. Your firm then gets authorized access to review and manage each client's payroll from one dashboard. Billing and liability stay with the client's own entity instead of yours, which is exactly the separation a multi-client firm needs.

This changes if the firm itself owns several related businesses under one legal structure, rather than serving outside clients. In that case, Multi-Company Access on the firm's own login is the better fit, since those companies share real common ownership. The dividing line is ownership, not headcount. One owner with five entities wants MCA, while one firm with five separate client-owners wants Accountant Connect.

The Franchise Owner Adding a Third or Fourth Location

Franchise owners scaling past two or three locations hit a different threshold. At some point, adding companies one call at a time stops being efficient, since every new location repeats the same paperwork cycle. If you're opening several new entities in a short window, say so up front.

Tell your ADP representative you're scaling and ask about batch or multi-location onboarding, instead of repeating the single-company request each time. Each new location still needs its own IID, its own state tax registrations, and its own banking setup. A rep who knows you're adding four locations, not one, can plan for that. Sequencing the work as a batch is often faster than four separate requests handled one after another.

Four locations added one at a time, each taking two to three weeks, can stretch a rollout past two months. The same four locations handled as one batch request often finish inside a few weeks total. ADP processes the paperwork for all of them together, instead of restarting the intake conversation each time. Ask your rep directly whether your account qualifies for that batch path before you submit requests one by one.

What ADP Needs Before It Can Link a New Company

Before ADP links a second company to your account, it needs the same core information it collected when you first signed up. The new entity is a legal business in its own right. ADP treats the request like a fresh setup, not a minor edit. That means the new company's EIN, its state and local tax IDs, and the bank account it will use for payroll funding.

ADP also confirms basic business details, including the legal name, physical address, and pay schedule. These details decide how the new company's tax filings and payroll calendar get built. A pay schedule that does not match your existing company can also change how fast the first payroll goes out.

Missing paperwork is the single biggest reason a new-company request stalls. A representative cannot register a business for state unemployment insurance without the state ID. An incomplete request usually comes back to you with a follow-up call, rather than moving forward on its own. That extra round trip adds days to the whole process.

Businesses that gather their EIN confirmation letter, state tax registration numbers, and a voided check or bank letter before calling typically finish setup in one call. Skipping that prep work is the most common reason a simple request turns into several calls back and forth. A little paperwork upfront saves real time later.

Timing also depends on how much beyond payroll you're adding. ADP notes on its own site that some setups finish within about two days, while others take a period of weeks. Services beyond core payroll, like time tracking, benefits administration, or a dedicated HR package, take longer to configure than payroll alone.

If you only need the new company added for payroll and Multi-Company Access, tell your representative that clearly. Scoping the request narrowly is usually what keeps it on the faster end of that range. Asking for everything at once, on the other hand, almost always pushes the timeline out.

Three Businesses, Three Different Lessons

The mechanics above play out differently depending on what kind of business is adding a company. Three short cases show why. Each one teaches something the others don't, from how costs stack in practice to how the accountant relationship changes the whole setup.

Maria's Second LLC and the Billing Surprise

Maria ran a single dental office on ADP for six years before opening a second practice under a new LLC. She assumed Multi-Company Access would combine both practices under one bill, since she already paid one monthly ADP invoice. Her representative explained that MCA only shares the login.

Every company keeps its own separate charges, because payroll, tax filing, and any add-on services are priced and billed per legal entity. ADP's own customer data shows businesses can save an average of $1,500 a year in admin time. That saving comes from cutting duplicate logins and data entry, though, not from a shared bill.

Ortiz Bookkeeping and Accountant Connect

Ortiz Bookkeeping manages payroll oversight for nine small-business clients, and none of them share an owner or an EIN. Rather than asking ADP to link all nine companies to one Ortiz login, the firm uses Accountant Connect instead. Each client keeps its own ADP account and its own direct billing relationship with ADP.

The firm's staff gets authorized access to review and manage every client's payroll from a single dashboard. This is the setup ADP itself points accounting professionals toward when they manage several unrelated businesses. It keeps each client's books, billing, and liability cleanly separated from the others, which protects the firm as much as the clients.

Devon's New Locations and the Batch-Onboarding Threshold

Devon owns a growing coffee franchise. Three locations had already been added to ADP one at a time, each with its own multi-week onboarding call. Adding the fourth location on that same pattern felt like starting over. Devon's rep suggested treating the next expansion as a batch request instead.

That one change let ADP process the EIN, tax registration, and banking details for two new locations in parallel, rather than one after another. The lesson here isn't about cost or accountant access. It's that repeated single-company requests eventually cost more time than one clearly scoped, multi-location call with the right person.

Devon's first three locations each took roughly three weeks from first call to first payroll. Every request restarted the same intake questions from scratch. Batching the fourth and fifth locations together cut that combined timeline by more than a third. The franchise now flags every new location in advance, so its ADP rep can plan the paperwork before the lease is even signed.

Worked Example: Setting Up a Second Company Under One ADP Login

Here is what the timeline looks like in practice, using a hypothetical bakery group as the running example. Riverside Bakery already runs 14 employees on ADP under one company. The owner opens Riverside Wholesale, a separate LLC with 4 employees, and wants both companies reachable from one login.

Step 1: Contact your ADP representative or support. The owner calls the existing account's assigned representative, rather than emailing generic support. A rep already familiar with the account can move faster. The owner states plainly that Riverside Wholesale is a new legal entity that needs its own IID linked through Multi-Company Access.

Step 2: Provide the new company's core details. ADP requests Riverside Wholesale's EIN, its state tax registration numbers, its physical address, and a bank account for payroll funding. Because the owner gathered these documents before calling, the representative submits the setup request in that same call.

Step 3: ADP configures the new IID and tax setup. Behind the scenes, ADP registers Riverside Wholesale for state unemployment insurance. It also sets up the new company's payroll tax deposit schedule. This step can finish within two days for a payroll-only request, or run several weeks when more services are added.

Step 4: Confirm the Select Company screen appears. Once setup finishes, the owner logs in and sees both Riverside Bakery and Riverside Wholesale listed by name and IID. The owner runs the first Riverside Wholesale payroll for its 4 employees and confirms the deposits land correctly. From then on, the owner switches between both companies without any further setup calls.

From first call to first payroll, a payroll-only request like this commonly wraps up within one to two weeks. That is faster than the full multi-week range ADP describes for setups that also add benefits or time tracking. The two companies now receive two separate invoices each billing cycle, one per IID, exactly as Maria's case above described. Riverside Bakery's existing employees, payroll history, and tax filings stay untouched, since MCA only adds a new, fully separate company alongside the original one.

Mistakes to Avoid When Adding a Company to ADP

• Searching for a settings-menu button that doesn't exist. Hours get lost clicking through account menus for an "Add Company" option that ADP never built, when a short call to a representative would have solved it.
• Calling without the new company's EIN ready. A request without the federal employer identification number stalls immediately, because ADP cannot register the entity for tax purposes without it.
• Assuming one ADP bill will now cover both companies. Each company is billed separately once linked, so budgeting as if the invoice stays flat leads to a surprise on the next statement.
• Skipping the state tax registration step. Without a state ID for the new company, ADP cannot set up state unemployment insurance, which can delay the very first payroll run.
• Using Multi-Company Access when Accountant Connect fits better. Firms managing unrelated clients under one login create liability and access confusion that Accountant Connect is built to avoid.
• Adding several new locations one at a time instead of asking about batch onboarding. Repeating the same single-company request for each new location wastes time a scoped multi-location conversation would save.
• Forgetting to double-check which company is active before running payroll. Since Multi-Company Access keeps you logged into one login, running a payroll in the wrong company's session pays the wrong entity's employees.
• Expecting instant activation. Treating the new-company setup like flipping a software toggle, rather than a multi-day onboarding process, leads to missed pay dates for the new entity's first cycle.

Do's and Don'ts for a Smooth Multi-Company Setup

Do

• Do gather the new company's EIN, state tax IDs, and banking details before calling, since a complete request in one call is faster than a partial one that bounces back.
• Do tell ADP explicitly that you want Multi-Company Access, so the representative sets up the correct linked-login structure instead of a fully separate account.
• Do confirm the new company's pay schedule matches your plan, because a mismatched schedule can delay the first payroll run for the new entity.
• Do ask about the cost of adding the new company upfront, since pricing is quoted per business and depends on headcount and services, not a flat published rate.
• Do check which company is active before every payroll run, especially in the first few weeks after setup, to avoid paying the wrong entity's employees.

Don't

• Don't assume the new company's employees can be added under the existing company's IID, since mixing two legal entities' payroll under one company record breaks tax filings for both.
• Don't wait until the day before your first payroll to start the request, because setup can take days to weeks depending on the services involved.
• Don't skip Accountant Connect if you're managing clients rather than your own companies, since forcing unrelated businesses onto one login creates access and liability problems.
• Don't expect the new company to inherit the first company's tax elections automatically, because every entity registers its own withholding and unemployment insurance settings.
• Don't call generic support with no context if you already have a dedicated representative, since your rep already has your account history and can usually move faster.

Pros and Cons of Multi-Company Access

Pros

• One login for every company you own, which cuts down on password resets and separate sign-ins across a growing group of businesses.
• Fast switching between companies mid-session, so managing two payrolls back to back doesn't require logging out and back in each time.
• Consistent user experience across entities, since every linked company uses the same RUN Powered by ADP interface your team already knows.
• Centralized support relationship, meaning one ADP representative can typically speak to every company tied to your login instead of juggling separate contacts.
• Scales cleanly as you add more entities, since a fifth or sixth company links through the same process the second one did.

Cons

• No self-service activation, since every new company still requires a request to ADP rather than a setting you flip yourself.
• Separate billing per company, so Multi-Company Access does not reduce your total ADP costs even though it reduces login friction.
• Setup time varies and isn't instant, with some companies ready in days and others taking weeks depending on the services attached.
• Easy to run payroll in the wrong company by mistake, particularly for teams new to switching between entities on one login.
• Not the right tool for unrelated clients, since accounting firms managing separate businesses are usually better served by Accountant Connect instead.

What to Do Next

1. Confirm which situation applies to you: a single business adding one new entity, an accounting firm managing multiple clients, or a franchise scaling several locations at once.
2. Gather the new company's EIN, state and local tax registration numbers, physical address, and a bank account or voided check for payroll funding.
3. Contact your existing ADP representative, payroll specialist, or the support line, and state clearly that you want a new company linked through Multi-Company Access.
4. Ask for a cost estimate and an expected setup timeline before confirming, since both vary by headcount and the services you're adding.
5. Once ADP confirms the new IID is active, log in to check that the Select Company screen lists both entities correctly before running the new company's first payroll.
6. If the setup involves more than payroll, such as benefits or time tracking, confirm those services separately, since they often take longer than the core payroll link.

Frequently Asked Questions

Can I use one ADP login for two completely unrelated businesses?

Yes. Multi-Company Access links any number of companies you own to one login. This works even if the businesses don't share an owner, as long as ADP has set up the connection.

How long does it take ADP to add a new company to my account?

It varies. Some setups finish within about two days when only payroll is involved. Others take several weeks if benefits, time tracking, or other services are added.

Does adding a company change what I pay ADP?

Yes. Each linked company is billed separately based on its own headcount and services. Your total ADP cost rises when you add a company, rather than staying flat.

Can I remove a company from my ADP account later?

Yes, with ADP's help. Adding a company requires a request, and removing or deactivating one goes through your representative too, not a self-service setting.

Do I need a separate EIN for the new company?

Almost always. Each company is its own tax entity, so it needs its own federal employer identification number before ADP can register it for payroll.

Can employees be shared between two companies on the same ADP account?

No, not directly. Each company keeps its own separate employee roster. Someone working for both entities typically needs a record in each one, based on how the work is structured.

What does IID mean in ADP?

It stands for interactive identification number. ADP assigns one to every company on its platform. It's the code that ties one business's payroll, taxes, and billing together.

Can my accountant add a company to my ADP account on my behalf?

Yes, in most cases. Your accountant or bookkeeper can call your ADP representative with you, or use Accountant Connect instead if they manage several unrelated clients.

Does Multi-Company Access cost extra by itself?

Not as a separate line item. The feature itself typically isn't an added fee, but each company it connects still carries its own full payroll and service charges.

Can I run payroll for two companies on the same day?

Yes. You process each company's payroll separately from the Payroll Selection screen after switching companies, since payroll runs never combine across two IIDs.

What happens to direct deposit when I add a company?

It's set up fresh for the new entity. The new company needs its own bank account and its own direct-deposit setup, since payroll funding ties to each company's own banking details.

Is Multi-Company Access available on the ADP mobile app?

Yes. ADP's mobile app supports the same Select Company screen used on desktop. You can switch between linked companies from your phone once MCA is active on your login.