What is a sliding-scale royalty in mining?

A sliding-scale royalty is a royalty whose rate changes with the metal price rather than staying fixed. A schedule in the contract sets a lower rate below a price threshold and a higher rate above it, sometimes across three or more bands. The result is that royalty revenue rises faster than the metal price in a rally and falls faster in a downturn, unlike a standard fixed-rate NSR which moves one-for-one with price. That only holds between the thresholds: above the highest band the rate stops rising and the royalty behaves like a fixed NSR again.

How do you model a sliding-scale NSR royalty in a valuation?

Make the royalty rate a function of the price assumption, not a constant. In each price scenario, look up the contractual rate for that price, then apply it to the revenue base the contract defines. Two contract details matter most: which price reference triggers the tier (spot at delivery, a monthly or quarterly average, or realised price), and whether the tier rate applies to all revenue or only to the band above each threshold. Modelling a sliding-scale royalty with one blended flat rate misprices it in every scenario except the one the blend was calibrated to.

Does the higher royalty rate apply to all revenue or just the amount above the threshold?

It depends on the contract, and the two readings give very different answers. Most schedules reset the whole rate: once the price crosses the threshold, the new rate applies to the entire sale, which creates a discontinuous jump in the payout. Some contracts apply rates band by band, like marginal tax brackets, which smooths the jump. Nothing in the term 'sliding scale' tells you which one you have. Only the agreement does.

Why are sliding-scale royalties common on development-stage deals?

Because they price the disagreement between the financier and the operator about future metal prices. The operator gets a lighter royalty burden at low prices, exactly when its margins are thinnest, which makes the financing easier to accept. The royalty buyer gives up some downside revenue in exchange for leveraged upside if prices run. On development-stage projects, where the financing gap is largest and price views diverge most, that trade suits both sides.

How Sliding-Scale Royalties Change the Model

Educational analysis for professional use. This guide is not investment advice or a recommendation to buy or sell any security, and it is not personalised.

Why a Flat Rate Is the Wrong Shortcut

A sliding-scale royalty pays a rate that changes with the metal price, so a model that plugs in one flat rate misprices it in both directions: too rich in the downside, too cheap in the upside.

A standard NSR royalty is linear. NSR is net smelter return, a percentage of the mine’s revenue after the smelting, refining and transport charges the contract allows. If gold rises 20%, the royalty cheque rises 20%, and every sensitivity table in a sum-of-parts valuation quietly assumes that proportionality. A sliding-scale royalty breaks it. The rate itself steps up as the price crosses contractual thresholds, so the payout accelerates through a rally and gives way faster through a sell-off than the price does.

The modelling mechanics are below. For royalty taxonomy, what an NSR deducts, and why an NPI deserves a discount, see NSR vs NPI vs GOR royalties. That page is claim type; this one is how a price-linked claim pays out.

A Worked Schedule

The cleanest way to see the mechanics is a three-tier schedule. The thresholds below are invented, and real schedules differ in where the steps sit, how many there are and which way they run. They are set around the $3,500/oz long-term gold price this site runs, so the base case lands in the middle band.

Gold price band	Royalty rate
Below $3,000/oz	1.5%
$3,000 to $4,000/oz	2.5%
Above $4,000/oz	3.5%

A schedule like that leaves out the thing that decides the payout, and no amount of staring at it will reveal which way the contract goes. Most are written whole-rate: whichever band the reference price falls in, that band’s rate applies to all of the period’s revenue. Some apply the rates band by band instead, like income tax brackets, so only the slice of the price above each threshold earns the higher rate. Both are called sliding scales, the two readings pay very different amounts, and only the agreement tells you which one you own.

Direction is not fixed either. A scale can step down as the price rises, which is how an operator caps what the royalty costs it in a strong market. Check which way yours runs before assuming a rally helps the holder.

The Payout Maths

Run the schedule against a fixed 2.5% NSR and the shape shows up at once. The comparison below reads the schedule whole-rate, so each rate applies to the full sale value per ounce.

Gold price	Flat 2.5% NSR payout	Sliding-scale rate	Sliding-scale payout
$2,600/oz	$65.00/oz	1.5%	$39.00/oz
$3,200/oz	$80.00/oz	2.5%	$80.00/oz
$3,500/oz	$87.50/oz	2.5%	$87.50/oz
$4,100/oz	$102.50/oz	3.5%	$143.50/oz
$4,400/oz	$110.00/oz	3.5%	$154.00/oz

The sliding-scale column bends away from the flat one. That is convexity: the payout curves upward instead of tracking price in a straight line.

Leverage runs both ways. From $2,600 to $4,400 the gold price rises 69%. The flat NSR payout rises 69% with it, from $65.00 to $110.00 per ounce. The sliding-scale payout rises 295%, from $39.00 to $154.00. Reverse the move and the same leverage works against the holder: the sliding-scale royalty gives up far more revenue on the way down than a fixed NSR does.

The thresholds create cliffs. On a whole-rate schedule, a $2 move in gold from $3,999 to $4,001 lifts the payout from about $100 to about $140 per ounce, a 40% jump on a 0.05% price move. A sensitivity table built on smooth percentage increments will step right over that cliff and never show it.

The top band is the last step. Above $4,000 the rate stops rising, so the royalty reverts to an ordinary 3.5% NSR and the payout goes back to tracking gold one-for-one. Convexity lives between the thresholds. Beyond the highest one the holder’s upside is linear again, and a schedule with a low top band is a real cap on what a rally is worth to them.

No single flat rate reproduces the profile. A 2.5% blend matches the schedule only inside the middle band. Calibrate the blend at your base-case price and every other scenario in the model is wrong, with the error largest exactly where the analysis matters most, in the tails.

Four Contract Questions Before You Model Anything

The schedule is the easy part. What the royalty actually pays depends on terms the headline tiers do not reveal.

Which price triggers the tier? Spot on the date of each sale, a monthly or quarterly average, or the operator’s realised price all produce different payouts from the same schedule. An averaging mechanism smooths the cliffs; a spot trigger does not.
Whole-rate or banded? Settled above, and the first clause to find in the agreement, because nothing in the schedule itself gives it away.
What is the revenue base? A sliding-scale NSR still deducts smelting, refining, and transport before the rate applies, and the permitted deductions vary by agreement. The deduction mechanics are covered in the royalty-type guide.
What else is bolted on? Buy-back rights that let the operator repurchase part of the royalty at a fixed price, caps on cumulative payments, rate step-downs after a production threshold, and area-of-interest clauses all change value materially and none of them appears in the headline rate.

Hybrids and Floor-Plus-Profit Structures

Hybrid royalties cannot be approximated with any single rate, sliding or flat, because their two components respond to different variables.

A floor-plus-profit structure pairs a fixed minimum NSR with a profit-linked top-up. In a weak year it behaves like a small NSR: revenue-based, predictable, indifferent to the operator’s costs. In a strong year the profit component dominates and the royalty takes on the exposures of an NPI, a net profits interest, which pays on profit as the contract defines it rather than on revenue. That means the operator’s costs now sit between the holder and the cheque, along with the operator’s incentive to load the pool with overhead and sustaining capital. One instrument, two regimes, and the model needs both legs computed separately under each price scenario.

Royalties that convert need the same two-regime treatment. The common case is a rate that steps once the operator has recouped its capital. Streams sit further away still: the holder buys metal at a delivery price per ounce rather than taking a percentage of revenue, and is modelled differently again; see how to value a metal stream.

Why These Turn Up on Development-Stage Deals

They cluster on development-stage royalty financings because they price a disagreement: the financier and the operator do not share a view on where metal prices go, and the schedule lets each of them fund the part they believe in.

Fixed royalties bite hardest when prices are low and a new mine’s margins are thinnest; a sliding scale lightens the load in those years. The buyer gives up some of that downside revenue in exchange for leveraged upside if prices run. Both sides get the asymmetry they want, which is why the structure keeps appearing where the financing gap is widest.

For the analyst this stacks two complications. Development-stage royalties already attract a higher discount rate than producing ones, and the rate choice is its own exercise; see mining discount rates by jurisdiction. Add a price-linked rate schedule and the asset’s cash flow becomes a joint function of the price deck and the contract, with neither reducible to a single number.

This is also why the asset-level NAVs of the listed royalty companies have to be built contract by contract. Portfolios such as Royal Gold’s and OR Royalties’ hold royalties of several types alongside streams, and a model that applies one generic rate across hundreds of agreements is not a model of the portfolio, just a guess at it.

Building It Into the Model

Make the royalty rate a function of price inside the model, then let every scenario recompute it.

In practice that means one lookup: for each price scenario, find the contractual rate for that price, apply it to the contractual revenue base, and only then discount. The asset’s annual cash flow becomes an output of the price assumption rather than an input held constant across scenarios. Sensitivity tables need price points on both sides of each threshold, otherwise the cliffs never show up.

A flat input hides those cliffs and misstates the tails even when the middle band looks right. The full sum-of-parts framework, including how asset-level cash flows roll up to a portfolio NAV, is in the Royalty & Streaming Sector Primer.