Price assessment is the determination of the prevailing market price for a crude oil or petroleum product at a point in time.
The most important price assessments are for the spot market for crude oil and products, as these are the best indicators of overall market conditions and are used as the benchmarks for many crude and product transactions.
Price assessment is performed by a number of price assessment agencies. The most important being:
Platts - assesses prices for spot trades of most major crude and product grades around the world
Argus - assesses prices for spot trades of most major crude and product grades around the world
OPIS - primarily assesses prices for rack (wholesale) and retail product markets
These agencies assess and publish prices on a daily basis based on observed transactions and/or player postings. Each has its own method for collecting transaction data, judging which transactions to include, adjusting for differences (eg quality, location, deal size), and reporting prices to the market.