Berkshire Hathaway, the conglomerate long headed by Warren Buffett, owns dozens of stocks in its massive public equities portfolio. Investors would be wise to look here for potential buying opportunities.One unstoppable financial stock with a 15% weighting in the Oracle of Omaha's portfolio has soared 58% in 2024 (as of Dec. 9). Should you invest $100 in this company right now?Unique position in the payments landscapeThe financial services business that has crushed the market this year is credit card heavyw ...