In a letter posted by the SEC on October 25, 2010 (SEC Letter), the federal regulator announced completion of its review of the 2009 10-K of Warren Buffett's Berkshire Hathaway. The SEC stated that it has accepted Berkshire's decision not to write down some $1.8 billion in losses that the SEC had initially questioned.

In April, the SEC sent Berkshire a letter (SEC Letter) questioning, among other things, Berkshire's disclosure of the substantial unrealized loss, which Berkshire acknowledged had been in the unrealized loss position for at least twelve months. Recognizing that Berkshire did not employ "bright-line" tests in determining whether an impairment was temporary or other than temporary, the SEC nonetheless opined that the duration of the loss appeared to be a "strong indication that these losses are not temporary." In May, Berkshire responded (Berkshire Response) with a detailed justification for its decision not to write the losses down.

Though Berkshire agreed that under accounting principles generally accepted in the U.S., disclosures are required for unrealized losses that remain in that position continuously for more than twelve months, it noted that it had considered the business prospects of the issuers, and in light of its intent to hold the securities until fair value was recovered, its treatment was warranted. In particular, Berkshire explained that much of the unrealized loss was concentrated in two issuers, Kraft Foods and U.S. Bancorp, and that despite the housing and credit crisis, each company reported significant earnings in 2009.