Warren Buffett's Berkshire Hathaway Inc. (BRKA, BRKB) took a stake in MasterCard Inc. (MA) in the first quarter, while Steven Cohen's SAC Capital increased stakes in retail and consumer services companies, according to a pair of regulatory filings on Monday.

Berkshire Hathaway, one of the world's most closely followed investment vehicles, disclosed it held 216,000 MasterCard shares. The holding, which comes as a new investment manager took over a chunk of the company's $53.6 billion equity portfolio, is valued at about $60 million based on Monday's closing share price.

Cohen, whose SAC Capital reported a 9.3% increase in securities holdings in the quarter ended March 31, increased a stake in consumer electronics retailer Best Buy Co. (BBY) to 2.3 million shares from 53,306 at the end of the previous quarter. SAC also more than doubled its stake in BJ's Wholesale Club Inc. (BJ) to 2.8 million shares from 1.1 million.

SAC also raised its stakes in insurers; Chubb Corp. (CB) holdings were up to 2.3 million shares from 24,198, while XL Group PL (XL) holdings were at 4.4 million shares from 239,564.

The disclosures are part of a quarterly filing requirement for investors who manage more than $100 million. The form, known as a 13F, must be filed within 45 days of the end of each quarter and many money managers wait until the last possible moment to submit their filings to the U.S. Securities and Exchange Commission. The filings give the public its freshest possible glimpse into the portfolios of well-known money managers.

The Bill and Melinda Gates Foundation, George Soros, activist Carl Icahn and a host of other investors disclosed their holdings on Monday. Few themes emerged, with some investors tinkering with their portfolios and other making wholesale changes. Some investors cut their gold investments, while others added to their positions. Some investors expressed enthusiasm for consumer names.

The Gates Foundation, the world's largest private philanthropy, ended the quarter with total stock holdings of $15.5 billion, a 2.6% increase since its last filing for the period ending in December.

The philanthropy, created by Microsoft Corp. (MSFT) co-founder Bill Gates and his wife, held stakes in the same 28 companies it reported holdings in last period, but it adjusted just a few. The foundation sold "B" shares in Berkshire Hathaway and Coca-Cola Co. (KO) and increased its holdings of Coca-Cola Femsa SAB (KOF) and Ecolab Inc. (ECL). The largest holding in the trust is 89 million B shares of Berkshire Hathaway with a value of $7.15 billion.

Soros's hedge fund sharply cut its stake in the SPDR Gold Trust (GLD), a gold-backed exchanged-traded fund, by almost 99%, to 49,400 shares. The fund also cut its position in mining company NovaGold Resources Inc. (NG).

Soros also cut its positions in J.P. Morgan Chase & Co. (JPM) and Bank of America Corp. (BAC) in the quarter ended March 31. Instead, Soros loaded up on shares of Citigroup Inc. (C) and Wells Fargo & Co. (WFC).

David Tepper's Appaloosa Management, which reported total holdings fell 14% from the previous quarter to $4.21 billion on March 31, also focused on bank stocks, reducing his holdings after aggressively boosting his bets in the sector in late 2010. Tepper cut his stakes in Citigroup by 35% and Well Fargo by 59%.

Tepper also initiated positions in several home building and energy companies.

Icahn reported a new stake in Amgen Inc. (AMGN), in which he purchased more than 1 million shares for his Icahn Capital LP fund. He also purchased 186,154 shares in energy distribution company Southern Union Co. (SUG).

As previously disclosed, Icahn increased his stake in Dynegy Inc. (DYN), and in March, had two of his nominated directors named to the board.

Hedge-fund manager John Paulson, who made his name betting against subprime mortgages in 2007, turned bullish on gold and bank stocks in recent years, and the latest glimpse into Paulson & Co.'s portfolio suggests his outlook hasn't changed much. Paulson reported more than double the previous stake in Barrick Gold Corp. (ABX) and only minor adjustments to his stakes in AngloGold Ashanti Ltd. ADRs (AU) and Kinross Gold (KGC). His holdings in financial stocks include Bank of America, Citigroup and Wells Fargo.

Paulson also disclosed a position in technology giant Hewlett-Packard Co. (HPQ), which has seen a management change over the past year. On Monday, the technology giant moved forward its earnings announcement to Tuesday after a memo from Chief Executive Leo Apotheker warning of tough times leaked to the media.

Greenlight Capital Inc., run by David Einhorn, built new positions in Best Buy Co., CVS Caremark Corp. (CVS), General Motors Co. (GM) and Yahoo Inc. (YHOO), among others.

During the quarter, Greenlight accumulated about 6 million shares of Best Buy, a position that is valued at about $192.8 million as of Monday's closing price. It also added 3.5 million shares of CVS Caremark, 3.4 million shares of General Motors and 8.5 million shares of Yahoo.

Greenlight reported holdings valued at $5.2 billion as of March 31, a 6% sequential increase. At the end of the fourth quarter Greenlight reporting holdings valued at $4.9 billion.

Activist investor Bill Ackman's Pershing Square Capital Management L.P. exited four names during the quarter, while increasing holdings in three others. The hedge fund manager, whose long-only equities positions dropped 7% in value to $5.42 billion, exited Automatic Data Processing Inc. (ADP), General Motors and Target Corp. (TGT). Pershing also said it had gotten rid of its holdings in Correction Corp. of America (CXW) as of May 16.

Pershing Square raised its stakes in real estate company Alexander & Baldwin Inc. (ALEX) and General Growth Properties Inc. (GGP), as well as Kraft Food Inc. (KFT).

Philip Falcone's Harbinger Holdings, which bet against subprime-backed mortgage bonds, reported it initiated new positions in Genon Energy Inc. (GEN) and Bunge Ltd. (BG), an agribusiness company. It also sold off more than a third of its stake in The New York Times Co. (NYT).

Harbinger also increased its stake in its own publicly traded unit, Harbinger Group Inc. (HRG), after selling one of its holdings, Spectrum Brands Holdings Inc. (SPB), to the listed affiliate.

The value of Harbinger's reported equity assets fell 34% from the previous quarter, to $1.06 billion.

FrontPoint Partners built positions in American Express Co. (AXP) and MetLife Inc. (MET), as well as more than a dozen other companies, during the quarter. The Greenwich, Conn.-based firm reported equity holdings valued at $898 million as of March 31.

FrontPoint reported it held a position of about 266,000 shares of American Express, valued at about $13.3 million as of Monday's closing price, and a stake of about 391,000 shares of MetLife, valued at about $17.2 million. It also built new stakes in retailers Skechers USA Inc. (SKX), OfficeMax Inc. (OMX), Big Lots Inc. (BIG) and BJ's Wholesale Club.

Investor Nelson Peltz reported no new holdings through his Trian Partners investment funds in the first quarter after taking on a new stake in Kellogg Co. (K) at the end of last year.

Trian had $9.4 billion invested, same as at the end of December. Trian Partners requested confidential treatment for some of its holdings.

Third Point LLC, run by hedge fund manager Dan Loeb, added consumer and energy names, including department store chain Big Lots and Tesoro Corp. (TSO), according to its filing. The hedge fund manager, who started accumulating both physical gold and gold-related holdings late last year, added to shares in exchange-traded SPDR Gold Trust. His gold ETF stake was worth $31.5 million.

Berkshire said it had omitted some information on its holdings in the filing, an action some investment managers take when they're building a new position.

The addition of MasterCard to the portfolio could be the work of Todd Combs, the former hedge-fund manager who was tapped by Buffett to manage a portfolio of about $2 billion to $3 billion at Berkshire. Combs was selected as the company prepares for the day the 80-year-old Buffett will no longer run Berkshire.

Berkshire also disclosed a reduced stake in oil producer ConocoPhillips (COP), trimming the holding less than 1% to about 29 million shares.

--Steven D. Jones, Roger Cheng, Thomas Gryta, Amy Or, Brett Philbin, Corrie Driebusch and Brendan Conway contributed to this story.

-By Erik Holm and Liz Moyer, Dow Jones Newswires; 212-416-2892; erik.holm@dowjones.com