In addition to Berkshire's permanent equity holdings, Berkshire also maintains interests in other equity marketable securities. In 1993, these holdings included General Dynamics, Wells Fargo, Gilette, Federal Home Loan Mortgage Corp. and Guinness plc.
The main difference between Berkshire's permanent equity holdings and marketable equity holdings is on the sell condition. With the permanent holdings, Buffett has indicated that Berkshire will not sell those holdings. The reason why Warren wouldn't sell the permanent holdings is believed to be due to the personal relationships he has with those company's managements. However, the buy criteria for both permanent holdings and equity marketable holdings is the same. Buffett looks for a companies with strong underlying business economics available at attractive prices in the marketplace.
Once Buffett buys an equity marketable security, he is content to hold onto it indefinitely, provided the return on capital is sufficient, management is competent honest and shareholder friendly, and the market does not overvalue the business.