By Peter Switzer, Switzer Super Report

Not surprisingly, we've seen a bit of cautious negativity on stock markets this week with the Dow Jones off three days on a trot. So does this mean we're in the calm before the storm?

I don't think so, and beware silly stories from media experts desperate to find reasons for recent sell-offs, which have been small. Last night one news service tried to say "Greek woes" were to blame ? yeah, right.

The simple fact is global markets are in a profit-taking phase ahead of the early September revelations from the European Central Bank (ECB) and the European Union (EU) leadership. And all of this is making me jumpy about what I should do about BHP Billiton ((BHP)).

What about BHP?

When do I buy it? Should I go before the ECB's meeting on September 5, or should I wait until after? Another question could be, why would anyone want to buy BHP now?

That's an easy one to tackle, so I will take this first. I don't invest for one week's, one month's or even one year's time. I put a three-year outlook on my purchasing of great companies and I ask, will the share price be higher in two or three years' time?

Given its share price is around $33, even if it gets to $40 in two years, that's a $7 gain or 21%. Even if that happened in three years, that's 7% a year with dividends of around 3%, which totals up to 10% a year.

Why three years? I reckon the global economy will make a comeback sooner, especially if the ECB acts wisely in September, but it will take time and that's why BHP's share price could linger longer at low levels.

If the ECB screws up, I reckon the share price will tumble on a bad decision for the global economy, but if they get it right, then cyclical stocks will do OK and could even be great, but I'm not that optimistic.

Be greedy?

Clearly, my thinking on BHP is driven by my belief that Warren Buffett was absolutely on the money when he said he liked to "be greedy when everyone is fearful," and so maybe it's close to the time when I need to be greedy on BHP.

So, it gets down to my confidence in the Europeans. Of course, BHP is in the news after it placed $50 billion worth of expansion projects on hold, including Olympic Dam, but this will help its bottom line and I'm sure with the share price hovering at low levels, Marius Kloppers will be trying to pull off some smart plays to restore our faith in him.

I'm going to wait a few days and see how markets play out, but I suspect I will punt on the ECB. Of course, I could split my bet and buy half before and half after the decision, which could be wise, as a bad decision could actually give me a dollar cost averaging opportunity on a company I want for three years.

A lot is riding on this damn ECB meeting.