The mechanism
A paperboard escalation clause indexes the paperboard-affected portion to a published series instead of fixing it at signing. The benchmark is the BLS producer price index for Paperboard, Excluding Corrugated Paperboard in Sheets and Rolls, series WPU091411.
Paperboard is a real input cost in folding carton packaging, consumer goods cartons, and graphic board and displays work. Its price can move more over a contract term than a fixed-price contingency is built to absorb, so indexing the paperboard-affected portion moves that risk onto the published index instead of onto one party.
What's specific to paperboard
Folding-carton board is virgin-fiber heavy, so it tracks market pulp and kraft-mill energy far more than the recovered-fiber cycle that moves corrugated. A packaging contract has to choose corrugated versus boxboard deliberately: the two routinely move apart in the same quarter.
The calculation, step by step
- Base index value. The index value at the base period, usually the month of contract signing or bid submission.
- Current index value. The index value at the adjustment date, usually the month of delivery or invoicing.
- Ratio. Current value divided by base value.
- Adjustment. Apply the ratio to the paperboard-affected portion, not necessarily the whole contract.
Take a clause with a $180,000 paperboard-affected scope, a base index of 330.0, and a current index of 385.0. The ratio is 1.17, a 17% increase, so $30,600 is added to that scope.
Where clauses go wrong
The most common mistake is not naming a series code. "The paperboard index" is not a series. BLS publishes more than one paperboard-related series, so name the exact code, WPU091411, in the contract text.
Clauses also skip the averaging window. A single month's value swings more than a 3-month rolling average, so the clause should say which one applies. Publication lag gets left out the same way: BLS releases data on a delay and revises early figures, so the clause should say whether the preliminary or final value governs.
The last common gap is no cap or floor. With no cap, an index spike passes through in full, which can make a large adjustment commercially unworkable.
Related
- Escalation clause analyzer: paste a clause and see the formula, undefined terms, and risk score.
- How escalation clause base periods work
- Price adjustment caps and floors