In a news release, S&P's Laline Carvalho is quoted as saying, "This change reflects our view of the increasing importance of Berkshire Hathaway's noninsurance businesses relative to the group's consolidated operations."
After its substantial noninsurance purchases in recent years, including the freight rail carrier BNSF and food giant Heinz, three-quarters of Berkshire's cash flow comes from its noninsurance businesses, S&P notes.
Word of the shift accompanies S&P's announcement that it is no longer considering a possible one- or two-notch downgrade of Berkshire's credit rating.
It was placed on what S&P calls "CreditWatch Negative" in August due to uncertainty over how Berkshire would pay for its $37 billion Precision Castparts acquisition.
At the time, Buffett acknowledged to CNBC that the 21 percent premium in the deal was a "very high multiple for us to pay" that would require about $10 billion of borrowing.
S&P says, however, that it has concluded the purchase is "neutral" to its AA rating of Berkshire's debt. That analysis was done after S&P decided to reclassify the company as a conglomerate.
The new "stable" outlook reflects S&P's expectation that Berkshire "will continue to report solid profitability metrics, significant cash flow generation and strong EBITDA margins in the next two years."