In the second quarter, billionaire investor and Berkshire CEO Warren Buffett bought back $5.1 billion of his company’s shares, more than double what he has purchased before. This according to a recent article in Bloomberg.

The article reports that the buybacks came as Buffett “unloaded almost $13 billion of other companies’ shares, including airline stocks and some financials, in what was his biggest selling quarter in more than a decade.”

Given that Berkshire’s cash pile had bloated to a record $146.6 billion in June (partly due to the sale of airline shares in April), the development is cause for optimism, says Edward Jones analyst Jim Shanahan: “The buybacks are a relatively safe way to deploy capital in an uncertain environment. But it’s clear that’s not all he’s doing.”

In July, Berkshire bought natural gas assets and in recent weeks purchased at least $2 billion in Bank of America stock.

According to Bill Smead, CIO of Smead Capital Management, the buybacks signal that Berkshire is feeling optimistic about its standing in today’s market. He argues that it reflects Buffett’s understanding of “how out of favor his own stock is in relation to other investments you could make in other companies.”