BOSTON ( TheStreet) -- Billionaire investor George Soros' hedge fund made a big bet on Delta Air Lines ( DAL) in the fourth quarter, while keeping gold as its largest holding. Apple ( AAPL), maker of the iPad and iPhone, remained a top 10 position.

The fund, which serves wealthy investors, added 11 million shares to its Delta Air stake, bringing it to 14.7 million shares worth about $186 million, Soros Fund Management said in a Securities and Exchange Commission filing.

The fund's assets rose about 15% in the fourth quarter, to $7.7 billion, up from $6.7 billion on Sept. 30.

Despite having called gold a "bubble" investment in the past, Soros' fund added to its horde of the yellow metal in the fourth quarter. Gold is often considered a hedge against inflation and protection against a falling dollar. Commodities such as gold tend to be uncorrelated to the movements of stock and bond markets and so may serve as portfolio-diversification tools.

The SPDR Gold Trust ( GLD), a gold-backed exchange traded fund, remained the largest fund holding at $655 million in the fourth quarter, up by about 25,000 shares over the course of the three months. This year, its value is off 4% after gaining 29% in 2010, when the S&P 500 Index rose 15%.

>>View George Soros' Portfolio

The fund's fifth-largest holding is also pure gold, Novagold Resources ( NG), a Canadian gold miner, at a $184 million allocation. The number of shares owned was unchanged in the fourth quarter.

Novagold is a rollercoaster stock, up 317% in 2009, up 133% in 2010, and down 7% this year.

Among the other top 10 holdings of the Soros Fund in order of size are: agricultural products giant Monsanto ( MON), U.S. oil and gas exploration firm Plains Exploration and Product ( PXP), generic pharmaceuticals maker Teva Pharmaceuticals ( TEVA) and health-care claims manager Emdeon ( EM).

The following are three stocks that Soros added to in the fourth quarter:

If you liked this article you might like

Here Are the Best Elite Airline Status Programs

Here's Why New York Area Airports Score Low With Travelers

Stocks Dad Would Have Loved, And Why He Was Right

United Airlines Might Be Having an Identity Crisis That Is Worrying Wall Street