I often like to write about a group of favorite companies. I've been fortunate to have gained of lot of stock market experience from an early age and I've found that really successful companies are much more likely to remain long-term wealth creators. This, as opposed to mediocre companies trying to hit the big-time.

Accordingly, I continue to write about many of the same companies over and over again, because they have distinguished themselves as successful, wealth-creating organizations.

One such company that continues to be a real favorite is VCA Antech (NASDAQ/WOOF). Long-time readers of this column will know of my affinity for this veterinary hospital company.

To be honest, I'm a little surprised at how well the stock has done, even in recent weeks. VCA Antech continues to hit new stock market highs in a deliberate and seemingly continuous fashion.

VCA Antech is an excellent example of a successful mid-cap company. Its success on the stock market serves to illustrate many things, but one of the most important is "saleability."

This is a term I used to denote how well a "story," otherwise known as a company or stock, might get recognized by institutional investors. The fact of the matter is that stock market speculation (I call it speculation while others call it investing) is all about perception and relative values. What I'm getting at is that there is no one appropriate valuation for a stock, only the market's perception of its value over a period of time.

This is why the psychology of the stock market is so important in generating capital gains from your holdings. This applies to general market sentiment, but mostly to the individual story in question.

The next time you are seriously considering speculating in a stock, consider its saleability to portfolio and mutual fund managers over time. Ask yourself, does this story have long-term saleability to professional investors? VCA Antech does. The story just makes sense and the company's stock chart illustrates the point.