Stable, non-growth companies typically have much lower P/Es. There's absolutely no chance that Exxon will double in revenue in the next couple of years; that's entirely possible for Apple.

I agree. Most people are already Exxon customers. Most people aren't Apple customers.

I haven't had the time to look at the numbers myself recently, but I have heard from some oil industry friends that I know that Exxon is currently in a state of slow-motion liquidation.

From what they are saying, exploration and expansion has not really taken a high priority within the company in recent years, and the emphasis seems to be more on maintenance.

I don't really know about the extent to which this is true, but if this is the case then it could possibly explain the low p/e ratio.

Personally, I think that the problem with Exxon is that it is an oil company and oil prices are connected with world economic outlook. (Most economic activity requires energy, which oil just happens to be a great source of.)

World economic outlook is a bit grim right now, so Exxon's outlook is as well. When economic activity heats up again then oil prices will rise, and, at that point, I am quite sure that Exxon will be doing quite well again.

This post does not constitute investment advice.

Exxon's income is highly dependent on the price of oil. See their historical numbers: http://www.google.com/finance?q=NYSE:XOM&fstype=ii

With oil at lower prices ($80/barrel now), their net income can significantly fall.