What did Warren Buffett and his colleagues at Berkshire Hathaway BRK.B +0.87% with their $350 billion stock portfolio do last quarter? Investors will find out very soon.

Regulatory filings are expected to be released Tuesday, which should lift the veil. The focus for investors will be whether Berkshire Hathaway (tickers: BRK/A, BRK/B) has increased its stake in Taiwan Semiconductor Manufacturing TSM -1.37% (TSM) and whether it has continued to cut its longstanding stake in U.S. Bancorp USB -0.14% (USB).