New Delhi, April 12 -- The "real" price of oil may be more than $30 higher than the price that most investors track-and those elevated levels could keep gasoline prices high for much longer.

Most investors keep their eyes on the price of Brent or West Texas Intermediate crude-benchmark prices established in futures markets in Europe and the U.S. respectively. Both of those benchmarks were down 13% this week to a little under $100 per barrel, their largest drops since 2020.

But it's increasingly important for investors to watch spot prices-the price at which oil changes hands in the physical market. Right now, spot crude prices measured in the North Sea are trading above $135 per barrel, and earlier this week they rose to all-time highs ...