Continuing our highlights of Warren Buffett’s 2010 letter:

On Reporting and Misreporting: The Numbers That Count and Those That Don’t

Earlier in this letter, I pointed out some numbers that Charlie and I find useful in valuing Berkshire and measuring its progress.

Let’s focus here on a number we omitted, but which many in the media feature above all others: net income. Important though that number may be at most companies, it is almost always meaningless at Berkshire. Regardless of how our businesses might be doing, Charlie and I could – quite legally – cause net income in any given period to be almost any number we would like.

We have that flexibility because realized gains or losses on investments go into the net income figure, whereas unrealized gains (and, in most cases, losses) are excluded. For example, imagine that Berkshire had a $10 billion increase in unrealized gains in a given year and concurrently had $1 billion of realized losses. Our net income – which would count only the loss – would be reported as less than our operating income. If we had meanwhile realized gains in the previous year, headlines might proclaim that our earnings were down X% when in reality our business might be much improved.

If we really thought net income important, we could regularly feed realized gains into it simply because we have a huge amount of unrealized gains upon which to draw. Rest assured, though, that Charlie and I have never sold a security because of the effect a sale would have on the net income we were soon to report. We both have a deep disgust for “game playing” with numbers, a practice that was rampant throughout corporate America in the 1990s and still persists, though it occurs less frequently and less blatantly than it used to.

Operating earnings, despite having some shortcomings, are in general a reasonable guide as to how our businesses are doing. Ignore our net income figure, however. Regulations require that we report it to you. But if you find reporters focusing on it, that will speak more to their performance than ours.

Both realized and unrealized gains and losses are fully reflected in the calculation of our book value. Pay attention to the changes in that metric and to the course of our operating earnings, and you will be on the right track.