Analyze the return on investment (ROI) for Berkshire Hathaway Inc.'s investments in various companies:

• Apple Inc.: Initial Investment - $10,000,000, Final Value - $15,000,000
• Coca-Cola Company: Initial Investment - $8,000,000, Final Value - $10,000,000
• Bank of America Corp.: Initial Investment - $5,000,000, Final Value - $7,000,000
• American Express Co.: Initial Investment - $12,000,000, Final Value - $14,000,000
• Moody's Corporation: Initial Investment - $7,000,000, Final Value - $8,000,000

Compute the ROI for each investment and analyze the overall performance of the investment portfolio.