A tumultuous year in oil markets left the energy industry reeling and gave fresh impetus to a perennial debate: What is the best gauge of crude prices? The Covid-19 pandemic confined billions of people to their homes and shut or slowed portions of the global economy in 2020, crimping demand for oil. Depots, pipelines and vessels were flooded with crude, threatening to overwhelm the world’s ability to store it.

The crisis reached its crescendo in April, when the price of light, sweet U.S. crude futures dived below $0 a barrel for the first time. Some traders were paying others to take oil off their hands. “What we saw was the single largest demand event in history,” said Peter Keavey, managing director for energy products at CME Group, owner of the New York Mercantile Exchange, where U.S. crude futures trade.

Prices have since somewhat recovered. But those jarring moves of the spring added urgency to arguments about whether benchmarks used since the 1980s adequately reflect the modern oil market. Newer gauges, including Shanghai-traded futures and a contract for Abu Dhabi’s Murban crude that will make its debut in March, are expected to grow in popularity.

A lot is riding on the choice of benchmark for oil producers, traders, refiners, and investors. Individual investors who were betting on a rebound in prices were burned when U.S. crude futures tumbled below zero. The crash rippled through the physical market, where, for example, Saudi Arabia sets prices for exports to the U.S. using an assessment tied to futures prices.

The emergence of the U.S. as an oil-exporting superpower in recent years, combined with a rapid growth in Asian demand and sliding production in Europe, have transformed flows of crude around the world. The pricing system based on three benchmark crudes—West Texas Intermediate in the U.S., Brent in Europe and Dubai in the Middle East—has broadly stayed the same.