If your Appendix A worksheet shows your estimated annual USF contribution is under $10,000, you qualify as de minimis and are exempt from contributing to USF (47 CFR § 54.706). But exemption isn't always the better outcome. Here's how to think about it.

What changes if you file as de minimis:

You pay $0 USF contribution on your end-user revenue.
You still file Form 499-A annually (it's your status declaration).
You're also exempt from TRS, NANPA, LNP, and ITSP fees (Line 422/512 math excludes your contribution base).
You cannot issue a reseller certification to your upstream wholesale carriers — you don't contribute directly.
Your wholesale SIP / trunk provider will charge you their USF surcharge on the wholesale bill — and you have no way to pass that cost through to customers (you don't collect USF).

What changes if you waive and file as a regular contributor:

You owe quarterly USF contributions on your interstate revenue at the current USAC factor (typically 25-30% of your contribution base).
You can show your wholesale vendor your 499 Filer ID + reseller certification and they must stop charging you their USF surcharge on wholesale trunking.
You can collect USF surcharges from your own customers and remit them directly to USAC.
You file quarterly 499-Q forms (not just the annual 499-A).

The break-even math:

Let W = your annual wholesale SIP/trunk spend and s = your vendor's USF surcharge rate (typically 25-30% of the interstate portion of your wholesale bill). If you file de minimis, your unavoidable cost is roughly W × s × wholesale_interstate_%.

Let R = your own interstate end-user revenue. If you waive and file regular, your direct USF contribution is R × current_factor.

File de minimis when: your direct contribution (R × factor) would exceed your wholesale-side USF surcharge hit (W × s × wholesale_interstate_%). Typical case: carriers with many end-user customers + low wholesale purchasing.

Waive and file regular when: your wholesale-side USF surcharge hit would exceed your direct contribution. Typical case: small VoIP resellers who buy a lot of wholesale SIP trunks and have few direct end-user customers yet.

Concrete example — small VoIP reseller:

Annual wholesale SIP spend: $60,000
Vendor USF surcharge rate: 27%, interstate portion: 64.9% (safe harbor)
Wholesale USF hit if de minimis: 60,000 × 0.27 × 0.649 = $10,513/year
Own interstate revenue: $40,000
Direct contribution if regular filer: 40,000 × 0.27 = $10,800/year
These are nearly equal — the decision is roughly a wash financially. But the regular filer also gets the administrative benefit of showing wholesale vendors the Filer ID + reseller cert, which can be worth $200-500/year in handling effort saved.

Other factors:

Business plan / growth: If you expect to exceed the de minimis threshold next year anyway, the paperwork overhead of switching from de minimis to regular mid-year is worse than just filing regular now.
Customer-facing billing: Regular filers can add a line-item "Federal USF Recovery Fee" on customer invoices (Line 403). De minimis filers cannot — the fee must be bundled into the rate.
Audit risk: Both are equally audit-defensible, but misrepresenting de minimis status is a forfeiture trigger. If in doubt, waive.
Multi-entity affiliates: De minimis is tested on consolidated revenue across affiliated filers — if any affiliate exceeds the threshold, you cannot claim de minimis. Appendix A Lines 3-4 add affiliate interstate/intl revenue to your own.

Rule of thumb: If you mostly sell to end users and your upstream spend is modest, claim de minimis. If you mostly resell wholesale SIP and your upstream USF exposure exceeds your own contribution base, waive and file regular. When in doubt, run the numbers above with your actual wholesale invoice + revenue data.