We believe the math of common stock investing is pretty simple. When you buy a stock without leverage, you can only lose your original investment. Your gains can be unlimited over the longest term (long duration). Most of the benefit (90%) of diversification is reached by owning a twelve-to-eighteen stock portfolio, if the owners are willing to put up with the relatively random way returns are handed out over time. Valuation matters dearly to portfolio results. Stocks purchased at depressed prices (as a group) outperform those which are more expensive over longer-run time periods.

Common stock portfolio turnover creates expense and is the enemy of performance. Long-term common stock performance fits on a bell curve. In a portfolio of well-selected common stocks, most of the long-term gains are going to come from 20% of the portfolio. This is only true if the most successful shares are held to a fault.

Every stock which goes up ten-fold must have first doubled, tripled and quadrupled. The only good reason to sell shares in a successful common stock of high quality is if its share price gets “maniacal” or if it no longer meets our eight criteria for stock selection. In our view, maniacal pricing is two standard deviations away from a normal price to earnings (P/E) ratio over the past 20 years.

One hundred percent of the stocks that go to zero fall by 20%, 40%, and 60%, before ultimately losing 100% of their value. Poor stock price performance among our portfolio holdings requires us to refocus on the fundamentals to preserve capital. Other than maniacal pricing, worrying about the volatility of the stock price of fundamentally strong businesses is damaging to performance and success.

Our observation over 38 years is that no one can consistently predict either the stock market or the US economy. Therefore, breaking any of the mathematical disciplines mentioned above, based on stock market or economic predictions, has the potential to ruin the benefit of common stock investing. Paying someone to make directional stock market or economic predictions automatically reduces portfolio results. Stocks, as measured by Ibbotson and Associates, have outperformed the other major liquid asset classes over long stretches of time (30-50 years). However, to get this added return you must accept extreme variability of returns.

Connecting Simple Math to our Discipline

We hold our winners to a fault and over the years our goal is to reinvest paper profits into future wealth creation. Remember, in the Bible, love covers a multitude of sins. In common stock ownership, your big multi-year, many times your original investment winners cover a multitude of small losses. These losses are realized on stocks which met our eight criteria, but after our purchase didn’t produce going forward.

Is there any way to avoid corrections in stocks which you have done well on in the past, but are correcting gains from prior years or are being doubted in the marketplace? As we mentioned before, we take great pains to ask if companies are becoming “maniacally” priced, and if they are, we reduce ownership dramatically. Most of the heartaches in common stock investing are the stocks you sold for twice what you paid that ended up tripling in price ten years later.

Here are some real-life examples. First, we came out of the bear market bottom in 2009 with a 4% position in Starbucks (SBUX). It rose in value by 2012 to over 8% of the portfolio. The P/E ratio had risen from 12x to 35x and we began a lengthy trimming exercise which took us down to a 2% position by 2014. The stock kept rising in value until three years ago. With the price going flat for the last three years and the earnings growing, the P/E ratio has dropped to 22x earnings. We may not be that far away from becoming a buyer of the stock. We like owning a business with cult-like customers, which spells an addictive legal drug.

Currently, we have trimmed our holdings in some big winners over the recent years, our bank stocks and NVR (NVR), which builds homes under the trade name, Ryan Homes. We started our positions in Bank of America (BAC) and JPMorgan (JPM) in 2012 at approximately $8.00 and $34.50, respectively. These three stocks soared last year and have corrected sharply this year. We trimmed them due to temporary popularity, but are keeping most of the positions, because we think the US economy will be led by homebuilding and household formation. The velocity of money could rise and the banks could be in a multi-year period of earnings growth, and massive dividend growth in the case of BAC.

Therefore, even though we have more than tripled our money from the beginning and collected dividends along the way, we believe that these stocks are just as likely to double in the next five years as any stock we might buy brand new. They have strong and expanding moats and their great balance sheets are throwing off copious free cash flow. Even if an economic slowdown hits us temporarily, we like to remind everyone that they don’t ask for a divorce if their spouse’s affection slows down for six to twelve months and they shouldn’t divorce their stocks either.

We ended the month of May with what we believe to be an excellent portfolio of companies meeting our eight criteria for common stock selection. It trades for around 13x this year’s earnings, are looking at paying 2% in forward dividends, and are extremely inexpensive in relation to lower average quality holdings in the S&P 500 Index and the Russell 1000 Value Index. We like the odds of another good ten years for our shareholders and we want to thank them for their willingness to invest in long-duration timeframes.