The fallout from weekend drone strikes on Saudi Arabian oil refineries is the key story to watch today, leading to big moves in everything from the price of oil itself to the Norwegian krone to the FTSE 100.

Not surprisingly, US energy stocks are also rallying, with the widely-followed Energy Sector SPDR ETF (XLE) is trading higher by 3.6% as of writing. If the current gains hold through the close of today’s trade, it would mark the biggest one-day rally of the year for the sector:

(Click on image to enlarge)

Source: TradingView, FOREX.com

While today’s move is impressive, it notably trails the nearly 15% rally in oil prices and has only been enough to take the ETF back to the levels where it was trading back in late July (by contrast, the price of oil itself is at its highest level since May).

Drilling down a bit further, the table below shows the percentage of assets and the daily gain/loss (as of 1:30 pm ET) in each of XLE’s top 10 holdings:

Source: Refinitiv, FOREX.com. All data from 1:30 pm ET on September 16, 2019.

Looking at the above table, it’s clear that the relative underperformance of the two mega-cap conglomerates that account for over 45% of the overall sector, Exxon Mobil and Chevron, masks the strength in some of the industry’s smaller players. Given their lower levels of operating leverage and vertically-integrated structures, XOM and CVX may continue to lag the broader sector, making some of the other names in the table above better targets for traders who are bullish on the rest of the sector.