"To eliminate subjectivity, we therefore use an understated proxy for intrinsic-value – book value – when measuring our performance....Yearly figures, it should be noted, are neither to be ignored nor viewed as all-important. The pace of the earth’s movement around the sun is not synchronized with the time required for either investment ideas or operating decisions to bear fruit."
To demonstrate the value of this metric over intermediate time periods, the report (page 5) includes the exact same data aggregated into rolling 5 year periods. This exhibit is striking in regard to the extent to which the figures stabilize and present a much clearer picture of past performance.
This works particularly well for Berkshire, since it doesn't pay dividends. Book value is the aggregate of the entire financial history of the firms -- and includes all capital gains -- both realized and unrealized. And all the exceptions that are typically excluded from operating earnings.
Later in the report, a discussion of operating earning vs net earnings repeats numerous prior discussions:
"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."
Net earnings are a GAAP figure that is meaningful for most businesses, but is severely flawed for a firm with a large investment portfolio and atypical derivative contracts. Operating earnings exclude the change in derivative liabilities as well as realized capital gains and losses.
Since 2006, Berkshire has issued a press release with the non GAAP operating figures reconciled with the GAAP net income figures. They have included this statement (from 2007):
"In our earnings summary, we distinguish between what we call “operating earnings” and investment and derivative gains/losses. Berkshire possesses a huge reservoir (about $35.5 billion on June 30, 2007) of pre-tax unrealized investment gains. The cashing of these in any given quarter (or the realization of losses, for that matter) can materially distort net income figures as well as comparisons between periods. We do not wish investors to mistakenly focus on a bottom-line number affected by large investment gains that do not stem from economic accomplishments during the reporting period and that have no concurrent impact on the intrinsic value of the company. Both trends in our operating businesses and their health are best judged by income before all investment gains or losses."
The only thing missing from this explanation is the implicit assumption that the only additional information is the latest quarter's data. Everything else has already been published and presumably included in valuation of the company. Another way of stating this is that over a single quarter, operating earnings are much more appropriate for a firm like Berkshire than GAAP net income. The quarterly press releases stress this both in quarters where the headline net income figure is higher as well as lower than operating earnings.
Note that over the 3 year period, the largest items - unrealized capital gains/losses and their tax impact - net to a modest figure. This reflects the market crash in 2008 as well as the stock market recovery in 2009 and 2010.
Net income is clearly a better proxy for earning power (for lack of a better term) than comprehensive income. However, it includes realized capital gains/losses and derivative gains and losses. And also remember that GAAP is designed for all businesses in all industries -- and most businesses don't have any derivatives and have modest capital gains/losses.