Yes, I think we all need to take a deep breath and remind...

Yes, I think we all need to take a deep breath and remind ourselves that the craft of investing can be practised successfully in a number of hues. Those of us that are passionate about the game know that some of the best investors in the word practice a highly concentrated approach (some call it "focus") and others follow a highly diversified approach, and then there's an entire spectrum of skilled investors that sit in between.

It's all very well to suggest that SDI was a poor investing decision, in hindsight. The fact that it has now stumbled tells us nothing about whether the decision to buy 3 months ago, or even 3 weeks ago, was a good or bad one.

Sure, a skilled "focus" investor will (hopefully) have fewer stumbles, but he/she may also have fewer gains.

Investor A buys into business X, without having "all" the facts, but only invests 2% of his/her funds. Investor B waits until he has "all" the facts before committing 10% of his/her funds. Who has made the better decision?

There is no definitive answer.

Investor A has made a calculated bet that his/her knowledge was sufficient, at the time, to ensure an adequate expected return. He/she has a higher level of risk (higher spread of possible outcomes), which is mitigated via a reduced commitment.

Investor B reduces his/her risk, and thus can have a greater commitment. Investor B also runs the risk of a less attractive entry point (due to the longer lead time in his/her process).

Ultimately what matters is that the expected return and the risk (likely spread of possible outcomes) be gauged adequately on average. This will ensure that the portfolio, over its life, has an adequate expected return and risk.

How each individual decision transpires tells us very little. In fact, failure at the individual level (especially for Investor A, but also for Investor B) is a virtual certainty.

In short, in agreement with @mal85, this is a game of probabilities. For any of us to suggest that we have reduced risk, in any one decision (or even at the portfolio level) to zero, would be delusional.