She specifically cites Sarbanes-Oxley, which requires that "auditors audit both the financial information and controls in place," for increasing the heft of 10-Ks. At the same time, however, she notes that this requirement has improved earnings quality by providing "increased assurance that the information is more reliable."

Explaining, and Explaining, the Risks

Yet another major contribution, according to John May, a PricewaterhouseCooper partner, has come from the SEC's 2005 mandate that companies include risk factors in annual reports. "The SEC," he says, is "trying to get this type of information into its normal review process."

Goodwill impairment adds a "very subjective" element to 10-K disclosure, he says, because it often is difficult to concentrate "just those reporting units where there's a reasonable chance of impairment in the near-term."

Still, the increased disclosure requirements in some ways have improved the quality of information provided to investors, says May. "The FASB efforts on financial instruments and derivatives came about because of the desire to give investors more transparency," he notes. With the many new disclosures adding to the transparency, he says, "I think you have to balance that" against concerns over the size of the 10-K. Also helping with transparency has been the SEC's "plain English" directive, and other efforts, which help companies "think of (their 10-Ks) as more of a communications document."