Mega-Project Payroll Growth and Your Workers Comp Mod
Steris is building a $600M, 600,000-sq-ft facility in North Carolina. For the contractors landing that work, rapid payroll growth can move the mod and the premium in ways the bid never modeled.
Rapid payroll growth from a mega-project can raise your workers' comp premium even when rates hold flat. On $500,000 of added payroll at a $6.00 manual rate, a 0.10 mod swing is roughly $3,000 of annual premium before schedule credits and carrier LCMs (NCCI experience rating formula, 2026). The mod is the multiplier that scales with payroll, so winning big work changes the math.
Steris announced a $600 million, 600,000-square-foot surgical instrument facility in North Carolina in May 2025 (Gov. Cooper press release, May 2025). For the Southeast contractors bidding on that build, the headline number is the project size. The hidden number is what happens to their workers' comp premium when payroll scales fast.
The instinct is to think flat rates mean flat costs. They don't. The workers comp premium formula is manual rate times payroll times your experience modification rate (EMR or mod) times any carrier multipliers. Payroll grows when you land the job. The mod is the lever that scales with it.
Payroll growth changes the mod's dollar weight
Your mod is a ratio. It compares your actual losses to expected losses for your classifications and payroll size. When payroll jumps, the expected loss side of that calculation grows. The same dollar amount of claims now sits against a bigger denominator. In theory, a growing company with steady losses sees its mod drift toward 1.00 over time.
The problem is timing. NCCI experience rating uses payroll from prior policy periods, not current ones. A contractor who lands a Steris-scale project in 2026 won't see that payroll in their mod calculation until the 2027 or 2028 rating, depending on the split point and data reporting cycle. If the contractor had a bad claim year in 2024 or 2025, that mod is still live on the renewal. The big payroll arrives on top of an elevated multiplier.
Here is the sensitivity. On $500,000 of added payroll at a $6.00 manual rate, the base premium is $30,000. A 0.10 mod swing on that payroll is $3,000 of annual premium before schedule credits, debits, and carrier loss cost multipliers (NCCI experience rating worksheet, 2026). That is $3,000 the bid did not account for if the estimator used the old mod and the old payroll. On a $2 million payroll expansion, the same 0.10 swing is $12,000.
Subcontractor COI gaps are where mega-projects bite
Industrial builds of this scale run on subcontracted labor. Every sub without a valid certificate of insurance (COI) on file gets rolled into the general contractor's payroll at audit. That is not a hypothetical. It is the single most common finding in our reviews of Southeast contractor worksheets.
NCCI classification rules and North Carolina Rate Bureau (NCRB) filings treat uninsured subcontractor labor as the hiring contractor's own payroll (NCCI Scopes Manual, 2026 edition). The rate applied depends on the work performed, not the contract label. A sub doing framing at $28 per hour with no COI becomes roughly $58,000 of added payroll at the framing class rate. On a 1.15 mod, that is real money the contractor did not budget for.
The 1099 subcontractors problem compounds on mega-projects because the volume of subs is higher and the COI tracking is harder. A project with 40 subcontractors and a 10% lapse rate means four subs getting rolled into the audit. On a 12-month project, that can be $200,000 or more of unexpected payroll exposure.
Split payroll records and the audit trap
Construction contractors often have payroll split across multiple classifications. A worker who frames on Monday and finishes concrete on Wednesday should have time cards that break those hours by class. When the records don't exist, the auditor assigns all hours to the highest-rated classification.
On a mega-project with rapid hiring, the record-keeping discipline that existed on smaller jobs tends to slip. New foremen don't know the system. Time cards come in late. Overtime gets lumped into a single code. The payroll audit then assigns everything to the most expensive class on the policy, and the premium adjusts accordingly.
NCCI's own classification inspection program findings show that misclassification is one of the most frequent audit issues for construction firms (NCCI Classification Inspection Program, 2025). The bigger the payroll, the bigger the dollar exposure to a single classification error.
What an audit would check
An audit checks whether the mod on your current worksheet reflects accurate claim values and classifications before the mega-project payroll hits. It looks at whether subcontractor COIs are current and whether the tracking system can handle the volume a project of this scale generates. It examines whether your time-card system captures split-class hours at the crew level. And it confirms that the payroll figures feeding your next NCCI rating are the right ones, not stale or misclassified data from a period when the project had not yet started.
If you are bidding industrial work in the Southeast, send us your NCCI worksheet before the renewal cycle tied to that project. We review it at no cost and tell you whether the mod you are carrying into the bid is the one your file actually supports.