With the recent release of Berkshire Hathaway (BRK.A)(BRK.B)’s Annual Report, Warren Buffett called his company’s 2012 performance “subpar” despite growing book value $24.1 billion with a portfolio of 41 stocks valued at $75.3 billion.

The Forbes E-book On Warren Buffett The $59 Billion Philanthropist. chronicling 50 years of Buffett’s investment savvy and unprecedented giving, is available now for download.

In his most recent shareholder letter, Buffett said that Berkshire’s ownership interest in all four companies (American Express (AXP ), Coca-Cola (KO ), IBM (IBM ) and Wells Fargo (WFC )) is likely to increase in the future. At yearend, they have a total unrealized gain of $26.7 billion. Berkshire received $1.1 billion of dividends from those shares. Read the complete shareholder letter .

With a prevailing interest in DaVita Healthcare Partner (DVA ), Berkshire’s 2013 buying behavior seems to say this expanding health care provider of kidney-dialysis services is poised for growth in the U.S. and Europe. With the recent string of DVA adds to the Berkshire Hathaway portfolio — as of Feb. 27, 2013, its current DVA shares are 14,808,959. Here’s a review of the top four companies mentioned in Buffett’s shareholder letter: WFC, KO, IBM and AXP.

Buffett ’s Number one holding is currently Wells Fargo & Co. (WFC ), with a portfolio weighting of 20%, and 439,857,861 shares.

The massive bank Wells Fargo & Company serves one out of three households in the U.S. and in 35 countries. Buffett has commented on the excellent management of his favorite bank, Wells Fargo, ranked fourth in assets, but first in market value of its common stock of all U.S. banks. Considered one of the fastest recovering banks after the industry implosion, Wells Fargo management was responsible for turning the bank around several years ago. In the past, Buffett has cited the bank’s low-cost of funding, a powerful advantage in lending. Wells Fargo & Company is a corporation organized under the laws of Delaware and a financial holding company and a bank holding company registered under the Bank Holding Company Act of 1956, as amended. Wells Fargo & Co. has a market cap of $187.38 billion; its shares were traded at around $35.55 with a P/E ratio of 10.6 and P/S ratio of 2.2. The dividend yield of Wells Fargo & Co. stocks is 2.6%. Wells Fargo & Co. has had an annual average earnings growth of 1.5% over the past 10 years.

Buffett commented in a previous annual letter, “The banking industry is back on its feet, and Wells Fargo is prospering. Its earnings are strong, its assets solid and its capital at record levels.”

Warren Buffett ’s Number two holding is Coca-Cola Co. (KO ), with a portfolio weighting of 19.3%, for 400,000,000 shares.

A world-wide brand, the Coca-Cola Company (KO ), is known for its carbonated beverages as well as products like tea and juice. Approximately 75% of the company’s revenue is generated outside the U.S. The famous beverage is well known in almost every country in the world, including Africa.

Considered a very healthy company with consistent growth, Coca-Cola Co. had an annual average earnings growth of 9.6% over the past 10 years. Coca-Cola has a market cap of $172.16 billion; its shares were traded at around $38.63 with a P/E ratio of 19.6 and P/S ratio of 3.7. The dividend yield of Coca-Cola stocks is 2.6%. GuruFocus rated Coca-Cola with the business predictability rank of 5-star. Calling himself late to the party, Buffett has commented on the longevity of the Coke brand, which he bought in 1988 along with Freddie Mac. Buffett said of his new purchases at that time:

“In 1988 we made major purchases of Federal Home Loan Mortgage Pfd. (“Freddie Mac”) and Coca Cola. We expect to hold these securities for a long time. In fact, when we own portions of outstanding businesses with outstanding managements, our favorite holding period is forever. We are just the opposite of those who hurry to sell and book profits when companies perform well but who tenaciously hang on to businesses that disappoint. Peter Lynch aptly likens such behavior to cutting the flowers and watering the weeds.”

Buffett’s Number three holding is currently International Business Machines Corp. (IBM ), with a portfolio weighting of 17.3%, for 68,115,484 shares.

Buffett has praised IBM leadership for rescuing IBM from the brink of bankruptcy 20 years ago and making it into a successful business today. In last year’s annual letter, he cited IBM management’s extraordinary operational accomplishments, saying, “Their financial management was equally brilliant, particularly in recent years as the company’s financial flexibility improved. Indeed, I can think of no major company that has had better financial management, a skill that has materially increased the gains enjoyed by IBM shareholders.”

International Business Machines Corporation was incorporated in the State of New York on June 16, 1911, as the Computing-Tabulating-Recording Co. International Business Machines Corp has a market cap of $227.92 billion; its shares were traded at around $204.5 with a P/E ratio of 14.1 and P/S ratio of 2.2. The dividend yield of International Business Machines Corp stocks is 1.7%. International Business Machines Corp had an annual average earnings growth of 12.1% over the past 10 years. GuruFocus rated International Business Machines Corp. with the business predictability rank of 5-star .

Buffett’s Number four holding is currently American Express Co. (AXP ), with a portfolio weighting of 11.6%, and 151,610,700 shares.

Another Buffett favorite is American Express Company (AXP ). To create an entire value chain, American Express segmented its credit card and lending business into three businesses: U.S. card services, international card and global commercial services, and global network and merchant services. As owner of the entire value chain, AXP has created a profitable niche for itself in the financial service markets, offering a great potential for profits. With a closed looped of its own related products and services and marketing, AXP pricing has a built-in competitive advantage.

American Express Co. was founded in 1850 as a joint stock association and was incorporated in 1965 as a New York corporation. American Express Co. has a market cap of $69.06 billion; its shares were traded at around $62.5 with a P/E ratio of 16 and P/S ratio of 2.3. The dividend yield of American Express Co. stocks is 1.3%. American Express Co. had an annual average earnings growth of 5% over the past 10 years. GuruFocus rated American Express Co. with the business predictability rank of 3.5-star .