Berkshire Hathaway is getting hooked up with a $63 billion interest-free loan from the US government

AP Images Berkshire Hathaway held its annual meeting recently and released its first quarter report this past Friday, so there is no better time to examine the factors that have contributed to the uncommon success of Warren Buffett's conglomerate. Buffett watchers will often point to Berkshire's unique culture, the competitive advantages of its operating businesses, and Buffett's investing and deal-making acumen. These are indeed critical factors, but Berkshire Hathaway has some structural adv...