What's going on?

Shares of BP, the world�s fourth-largest oil company, slipped 4% on Tuesday after it reported a slide in its quarterly profit.

What does this mean?

BP�s third-quarter profit was 41% lower than the same time last year � but even that was better than investors expected. Oil prices are lower now than they were a year ago, which meant BP made less from its black gold. That was only partly made up for by earnings from the company�s refining business, which turns crude oil into products that businesses and individuals can actually use.

With global economic growth slowing � and demand for oil dropping as a result � there�s oil slick ahead for BP and its competitors, which could find it harder to grow future profits.

Why should I care?

For markets: Refining those refinery estimates.
About a third of BP�s profit comes from refining, compared to between a quarter and a third for a few of its rivals. Investors might look at the size and performance of those refinery businesses to see if they�ll be able to weather falling oil prices and declining demand too. But given all this competition, profit margins in the refinery business might yet come under pressure � so it might not stop some oil firms falling short of expectations. Just look at Shell, Total, and Chevron�s shares, all of which fell on Tuesday.

The bigger picture: Welcome to the party, Aramco.
According to reports on Tuesday, Saudi Aramco � the state-owned oil firm and the world�s most profitable company � will kick off the initial public offering process next week. It�s aiming to raise $20 billion in one of the largest stock market listings ever. First up, investors will meet with company analysts (and the company itself) to determine how much they think a share of Saudi Aramco is worth. And if the company�s happy to sell shares at that price, it�ll have listed by December and you�ll be able to buy (and sell) its shares.