The best outsourced accounts payable services for a mid-size company are the ones that score highest on your own weighted criteria: control evidence such as a SOC 1 Type 2 report, payment fraud safeguards, fit with your ERP, the people who will handle exceptions, and total annual cost at your real invoice volume. No single provider wins for every business, so the useful work is building a scorecard and making each bidder prove its answers.
This guide is for controllers and CFOs who have decided to hand AP to an outside team and now need to compare outsourced accounts payable services. If you are still deciding whether to outsource at all, or need the scope, segregation of duties and SLA detail, start with our guide to outsourcing accounts payable and come back here for the selection step.
Proposals for AP work come from four broad kinds of provider. They differ in who does the work, whose software runs the process and how much the service bends to your existing setup. Madras Accountancy, which publishes this guide, is an outsourced accounting firm and sits in the first category, so weigh our view of the categories with that in mind.
| Provider type | Who does the work | Whose system | Typical fit | Watch for |
|---|---|---|---|---|
| Outsourced accounting firm | Accountants who also handle your close, reconciliations or tax work | Usually your ERP or accounting system | Companies that want AP tied to month-end close and a named team | Depth of AP-specific automation; staff continuity |
| Business process outsourcing (BPO) provider | Large AP processing teams working to standard procedures | Often the provider's own capture and workflow tools, posting to your ERP | High, steady invoice volume across many entities | Minimum volumes, rigid change requests, long contracts |
| AP automation software with managed services | The software vendor's service team, or a partner it certifies | The vendor's platform, integrated with your ERP | Companies ready to adopt a new AP platform | You may be buying a platform change along with the service |
| Hybrid: your software, outside operators | An accounting firm or contractor working inside an AP tool you license | Your tool and your ERP | Companies that already own AP software and lack staff to run it | Split accountability between software vendor and operator |
The distinction that matters most is ownership of the workflow. When the provider's platform holds invoice images, approval history and vendor bank details, leaving later means a data migration. When the provider works inside your systems, switching is easier. For a broader view of the AP software side, our article on automated accounts payable solutions and their ROI covers what the tools do on their own.
A weighted scorecard stops the decision from drifting toward whichever sales team presented last. Agree the weights before any proposals arrive, then score each bidder from 1 to 5 on each line.
| Criterion | Suggested weight | What a 5 looks like |
|---|---|---|
| Controls and audit evidence | 25% | Current SOC 1 Type 2 covering the AP services you will buy, clean opinion, complementary controls you can actually perform |
| Total annual cost | 20% | Lowest normalized cost at your forecast volume, with exceptions, setup and minimums included |
| Payment fraud and vendor master security | 15% | Call-back verification on every bank change, dual review on new vendors, documented ACH fraud monitoring |
| System fit | 15% | Proven work in your ERP version, no file re-keying, approval history retained in your system |
| Service model and people | 15% | Named team, written exception process, US-hours coverage, low turnover on comparable clients |
| Transition and exit | 10% | Written onboarding plan, parallel run, data return in usable formats at no extra charge |
These weights are guidance for a typical mid-size company. A company with weak purchasing discipline might raise service model, since the provider will spend more time on exceptions. Score with evidence: a document, a demo or a reference call, never a sales claim alone. Our 30-point checklist for evaluating an accounting outsourcing provider has extra due-diligence items if your scorecard needs more rows.
The fraud row deserves its weight. In the Association for Financial Professionals' survey of 465 treasury practitioners, released 14 April 2026, 76% of organizations experienced attempted or actual payments fraud in 2025, and 74% were affected by business email compromise. An AP provider handles the vendor emails and bank-change requests those schemes target, and our primer on fraud prevention for business finances explains the common schemes in more detail.
Send every bidder the same questions and ask for written answers plus supporting documents, grouped so each answer maps to a scorecard row. Our template for building an accounting outsourcing RFP covers structure and timelines; the AP-specific questions below slot into it.
Volume and scope
Controls and evidence
Payments and fraud
Systems
Year-end and tax
People and exit
On the 1099 question, the rules changed for 2026. The One Big Beautiful Bill Act increased the $600 threshold in section 6041 to a base threshold of $2,000 for payments made after 31 December 2025, with inflation indexing for calendar years after 2026. Filing mechanics matter too: the 2025 IRS General Instructions for Certain Information Returns say that if you are required to file 10 or more information returns during the year, you must e-file, counted across all form types combined, and they describe TIN Matching as available to payers or authorized agents filing Forms 1099-MISC and 1099-NEC. Our explainer on the 2026 1099 reporting threshold covers the form-by-form changes.
The ACH question is specific to 2026. Nacha's Phase 2 fraud monitoring rules took effect on 19 June 2026 (practically 22 June, the next banking day). They apply to non-consumer Originators, Third-Party Service Providers and Third-Party Senders regardless of origination or transmission volume, and require risk-based processes reasonably intended to identify entries suspected of being unauthorized or authorized under False Pretenses, reviewed at least annually. A provider that sends ACH files on your behalf should be able to show you that process.
The AICPA describes SOC 1 as an examination of controls at a service organization that are likely to be relevant to user entities' internal control over financial reporting. AP touches liabilities, expenses and cash, so a SOC 1 is the report your external auditor is most likely to ask about. The Journal of Accountancy explains that a type 1 report covers the suitability of control design as of a specified date, while a type 2 report adds an opinion on whether the controls operated effectively throughout a specified period. That period of testing is why buyers usually ask for Type 2.
A real example helps. The US Treasury's Bureau of the Fiscal Service publishes the SOC 1 Type 2 report for its Administrative Resource Center, a shared-services operation whose description says it processes and records customer agency disbursements, including supplier invoices. The report covers the period 1 July 2024 to 30 June 2025, and the auditor's opinion on control design depends on subservice organizations and customer agencies applying "the complementary controls assumed in the design" of the service organization's controls.
When you review an AP provider's SOC 1, check these points:
SOC 2 covers security and data handling and is a separate question. Our comparison of SOC 1 vs SOC 2 audits explains which report answers which risk, and our guide to vendor risk assessment for offshore accounting covers ISO 27001 and data protection checks for providers working from other countries.
Proposals rarely line up neatly. Convert each one to a single annual figure at your forecast volume before you compare.
| Model | How it is billed | Works well when | Normalize by adding |
|---|---|---|---|
| Per invoice | A rate per processed invoice, often tiered by volume | Volume is steady and invoices are fairly uniform | Exception surcharges, monthly minimums, setup fees |
| Dedicated team (FTE) | A monthly fee for named staff hours | Many exceptions, complex coding, several entities | Overtime or surge charges, onboarding fees |
| Fixed monthly tier | A flat fee for a volume band | Volume is predictable within a band | Overage rates if you exceed the band |
| Software plus service | A platform subscription plus a service fee | You want to adopt a new AP platform | Payment fees, implementation, user licences |
Ask each bidder to state what happens when volume moves 20% up or down, since mid-size companies often grow through acquisitions or seasonal peaks. Write the agreed pricing mechanics into the contract; our guide on what to ask before signing an accounting outsourcing contract lists the clauses, and our article on offshore accounting SLA clauses covers service credits.
This example is illustrative. The company, providers and prices are invented to show the method and do not reflect market rates.
A distribution company with three entities processes 2,000 invoices a month, or 24,000 a year, and runs a mid-market ERP. It shortlists three bidders.
On a per-invoice basis that is $3.25, $2.75 and $3.00. Cost is scored as 5 multiplied by the lowest cost divided by each bidder's cost, giving A 4.23, B 5.00 and C 4.58. The other scores come from document review, demos and reference calls.
| Criterion (weight) | A score | B score | C score | A weighted | B weighted | C weighted |
|---|---|---|---|---|---|---|
| Controls and audit evidence (25) | 4 | 5 | 4 | 20.0 | 25.0 | 20.0 |
| Total annual cost (20) | 4.23 | 5.00 | 4.58 | 16.9 | 20.0 | 18.3 |
| Payment fraud and vendor master (15) | 4 | 4 | 5 | 12.0 | 12.0 | 15.0 |
| System fit (15) | 5 | 3 | 4 | 15.0 | 9.0 | 12.0 |
| Service model and people (15) | 5 | 3 | 3 | 15.0 | 9.0 | 9.0 |
| Transition and exit (10) | 4 | 3 | 3 | 8.0 | 6.0 | 6.0 |
| Total (out of 100) | 86.9 | 81.0 | 80.3 |
Each weighted figure is the weight multiplied by the score, divided by 5. Provider B is cheapest and has the strongest SOC 1, yet Provider A wins because it already works in the company's ERP and offers a named team for the multi-entity exceptions. A 5.9-point lead is narrow enough that the company should check A's references and SOC 1 scope before signing. Different weights could change the ranking, which is why they are fixed before proposals arrive. Teams comparing platforms during the same exercise may find our survey of the mid-market accounting tech stack useful context for the system-fit row.
What are the best outsourced AP services for mid-size companies? The best fit depends on your volume, ERP, entity count and audit needs. Score bidders on controls evidence, total cost, fraud safeguards, system fit, service model and exit terms, and pick the highest weighted total.
Do I need my AP provider to have a SOC 1 report? If your financial statements are audited, a SOC 1 Type 2 covering the AP service is the most useful evidence you can give your auditor.
What is a bridge letter? It is a letter from the service organization's management covering the gap between the end of the SOC report period and the present, stating whether controls have changed. Ask for one whenever the report period ended some months before your fiscal year-end.
How should I compare per-invoice and dedicated-team pricing? Convert both to an annual total at your forecast invoice volume, including exception charges, minimums, setup, payment fees and transition costs. Then divide by annual invoice count if you want a per-invoice figure for comparison.
Should an AP provider be able to release payments? Payment release should stay with your own staff, ideally with dual approval in your bank portal. The provider prepares the payment proposal and supporting detail.
Madras Accountancy publishes this guide and offers outsourced accounting support for US businesses, including accounts payable processing, bookkeeping, month-end close, 1099 and tax preparation, audit support and CFO advisory. If you are building an AP scorecard or reviewing provider proposals, contact our team to talk through your requirements.
The section 4960 excise tax is 21% of nonprofit pay over $1M. From 2026 it covers all employees. See the medical carve-outs, Form 4720 and a worked example.
The paid family and medical leave tax credit is permanent from 2026. See the 12.5% to 25% rates, the premium option, the 6-month rule and how Form 8994 works.
Opportunity zones become permanent in 2027 under the One Big Beautiful Bill. See the new deferral, rural bonus, and the 2026 handoff.
