Aug 14 (Reuters) – Warren Buffett’s Berkshire Hathaway Inc has eliminated its stakes in National Oilwell Varco Inc and Phillips 66, and on Friday signaled it may have another large investment in the works.

The changes were disclosed in a filing with the U.S. Securities and Exchange Commission detailing Berkshire’s U.S.-listed stock portfolio as of June 30.

Berkshire (BRKA) said it disclosed some information about its holdings confidentially to the SEC, which the regulator sometimes permits when Buffett is building a large new position.

Last week, Berkshire disclosed it had bought $3.09 billion of equities in the second quarter, without identifying the stocks.

(Reporting by Jonathan Stempel in New York; Editing by James Dalgleish)