Warren Buffett's Berkshire Hathaway was a net seller of stocks last quarter — and slowed its share buybacks

In the fourth quarter of the year, Warren Buffet's company was a net seller of stocks, but reduced its share repurchases, which resulted in a slight reduction in its massive cash pile.

The conglomerate spent about $3.4 billion on stocks on a net basis last quarter, but sold $3.9 billion worth, meaning it was a net seller of equities in all four quarters of the year. A fraction of its $331 billion stock portfolio was sold over the course of last year.

Over the past two years, the company has spent over $50 billion on stock purchases. Since the start of the year, it has spent over $1 billion on repurchases, but this year it has only spent a small amount.

The cash pile was reduced from $149 billion to 147 billion as a result of the company's purchases. Over the course of last year, the team boosted their cash and cash equivalents from $45 billion to $85 billion, while decreasing their holdings of Treasury bills from $90 billion to $59 billion. It's possible that the team soured on government bonds because interest rates are going to rise soon.

The investor is willing to invest about $80 billion in the company. Since stocks are near record highs, private-equity firms and special-purpose acquisition companies have bid up the price of acquisitions, and even his own company's stock has grown more expensive, he has struggled to spend it.

See's Candies, GeICO, and the BNSF railroad are just a few of the businesses owned by the conglomerate. Its revenue grew 12% last year as sales jumped across its insurance, railroad, utilities, energy, and other main divisions.

Despite supply-chain disruptions due to the swine flu, the company still managed to grow pre-tax earnings from its operating businesses by 19% to $32 billion.

In his annual shareholder letter, which was published alongside the fourth-quarter results, billionaire investor Warren Buffet referred to his company as the "four giants" of it.

A recent portfolio update shows that the company built a $1 billion stake in the video game publisher and boosted its position by a third. On the other hand, it slashed several holdings.