USF Safe Harbor is Costing You Money
In our regulatory work, we're often surprised by how many providers don't know that they can lower their USAC obligation with a USF Traffic Study to their actual Percent of Interstate Usage (PIU) rather than using the FCC's Safe Harbor rate. Safe Harbor is a standard number that assumes that a pre-determined percent of a provider's calls (64.9% for VoIP, 37.1% for Wireless) were interstate or international in nature. In our experience, we've found that carriers' actual PIUs are typically around half of the FCC's Safe Harbor percentage.
What is a USF traffic study?
A USF traffic study is a statistically valid analysis of your call detail records (CDRs) that calculates your actual Percent of Interstate Usage (PIU) for Universal Service Fund reporting—instead of the FCC’s default safe harbor rates of 64.9% for interconnected VoIP and 37.1% for wireless. Reporting an inflated interstate mix can raise what you and your customers pay into USAC.
Why Safe Harbor Still Costs Carriers Money
The Federal Universal Service Fund (USF) is funded by contributions tied to interstate and international telecommunications revenues. The FCC sets a quarterly contribution factor; your assessable base is the jurisdictional slice that qualifies—not “all revenue.”
If you cannot or do not measure actual jurisdiction, the FCC allows safe harbor defaults. Those defaults were built for convenience, not accuracy. For many VoIP and wireless providers, real customer traffic is far more local/intrastate than safe harbor assumes.
Risks of Relying on Safe Harbor
- Inflate reported interstate/international revenue
- Increase USF contributions passed through to customers—or absorbed as margin loss
- Push borderline carriers over the de minimis contribution threshold, triggering direct USAC billing and quarterly Form 499-Q work
How an ATS USF Traffic Study Works
- Free sample / preliminary analysis — Send a subset of CDRs. ATS estimates whether a full study is likely to beat safe harbor and provides a fixed-scope quote.
- Collect CDRs — Full sample for the period that will support Form 499 reporting. ATS handles messy, multi-vendor formats.
- Classify Jurisdiction — Intrastate, interstate, international (and related handling per methodology).
- Compute PIU to the USAC Requirement — Designed for no more than 1% margin of error at 95% confidence, with documented sampling/estimation and bias controls (per USAC Form 499 training / instructions).
- Deliver an Audit-Ready Report — Prepared in the required format for submission to USAC, typically about one to two weeks after data receipt (per ATS FAQ).
- Apply Consistently — Use results on Form 499-Q forecasts and the annual Form 499-A for the same calendar year; retain supporting records as required
The same CDR foundation can also support adjacent analytics needs via ESAP CDR Analytics.
USF Traffic Study FAQs for VoIP and Wireless Providers
Is a traffic study cheaper than the 64.9% VoIP safe harbor for USF contributions?
It is when your actual interstate share is below 64.9%. Under the safe harbor, the FCC treats 64.9% of your interconnected VoIP revenue as interstate or international, and that amount is multiplied by the quarterly contribution factor, which is 42.0% for the fourth quarter of 2026. A traffic study replaces 64.9% with your measured percentage.
For example, on $1,000,000 of VoIP revenue, the safe harbor puts $649,000 in the contribution base, or about $272,580 at a 42.0% factor. If a study measured half the safe harbor (32.45%), the base would be $324,500, or about $136,290. This is an illustration only; your numbers depend on your traffic and each quarter's factor.
In ATS's experience, actual PIUs typically come in around half of the safe harbor, and every traffic study ATS has completed lowered the provider's USF contribution. Study cost varies with data volume and complexity. ATS quotes a fixed price after a free sample analysis, so you can compare it with your projected savings before you commit. Estimate your own numbers with the USF Savings Calculator below.
What does a wireless carrier need to file a traffic study with Form 499-A?
Cellular and broadband PCS providers that don't want to use the FCC's 37.1% wireless safe harbor can report their actual interstate and international share with a traffic study. Under the 2026 Form 499-A instructions, a carrier needs:
- A study of the right period: the study should cover the calendar year whose revenues are reported on the 499-A, using usage data such as call detail records (CDRs) to estimate the share of interstate and international minutes.
- A valid sample: sampling designed for a margin of error of no more than 1% at a 95% confidence level, with a written explanation of the sampling and estimation methods and why the result is unbiased.
- Correct treatment of billed toll: charges billed as interstate or international count as 100% interstate or international, and the safe harbor can't be applied to toll charges, USF pass-through charges or fixed local service revenue.
- Consistency: the same method on the 499-A as on that year's 499-Q forecasts, and the same choice (traffic study or safe harbor) for all affiliated wireless entities each quarter.
Form 499-Q forecasts are due February 1, May 1, August 1 and November 1. ATS builds wireless traffic studies from your CDRs to this standard and delivers the report in the format USAC requires, typically about one to two weeks after receiving your data.
USF Savings Calculator
Universal Service Fund Webinar - 2025
Our VP of Solutions Engineering Ryan Guthrie partnered with Jonathan Marashlian from the CommLaw Group and David Rubenstein from Wolters Kluwer to discuss the current state of the Universal Service Fund and Traffic Studies. Other topics discussed include;
- The Current State of the USF
- Data Retention and Record Keeping
- Alternative Revenue Allocation Methodology
- Traffic Studies
- Remaining Compliant and Competitive
Different Providers, Same Benefits
While the benefit of traffic studies to reduce USF costs is clear, there is more than one incentive for carriers to complete a traffic study. In every single traffic study we've completed, providers saw a decrease in their USF Contribution (seriously, every single one) . Here's how we've seen carriers benefit from them;
- VoIP and Wireless companies have an extremely high safe harbor rate of 64.9%, and 37.1%, respectively. In our history of traffic studies, most actual PIUs don't even come close to these safe harbor rates.
- De Minimis carriers that are close to the FCC's threshold use traffic studies to validate that they are indeed de minimis. If smaller providers use the safe harbor rate, there’s a much higher chance that their percent of interstate or international revenue will be over the de minimis threshold.
To be sure that you'll benefit from a traffic study, we offer a free analysis on a subset of data to get a good idea of how low your actual Percent of Interstate Usage is.
Download USF VoIP Case Study
What Carriers Say...
USF Resources
What's Next for the USF?
Blog
The wheels are turning on USF reform, and recently the FCC took small steps forward by asking Congress for authority to expand the contribution pool. Commissioner Brendan Carr predicts that if nothing is done, the contribution factor can hit 75% within four years, and some experts believe that it could be up to 40% in 2023.
Current Quarter's Contribution Factor
USAC
"The contribution factor is the percentage of end user revenue that will be contributed to the Universal Service Fund to support the universal service programs, as established by the FCC. The contribution factor changes every quarter."
USF Traffic Study - Wireless
Case Study
Wireless providers contribute to the Universal Service Fund (USF) with a Safe Harbor rate of 37.1%. Providers have to pay the USF Tax themselves, pass the increase to their customers, or take a closer look at their actual percentage of interstate usage.