Dec 21 (Reuters) - Ratings agency Moody"s on Tuesday upgraded Apple Inc"s (AAPL.O) long-term credit rating to "AAA" with a stable outlook, citing the iPhone maker"s "exceptional liquidity" and robust earnings. With this, Apple joins an elite club of companies including Microsoft (MSFT.O) and Johnson & Johnson (JNJ.N) that have been given Moody"s highest rating. "Apple"s very strong business profile reflects its substantial operating scale, a large installed base of products and users of its services, strong customer loyalty, and premium brand positioning," Moody"s analyst Raj Joshi said in a note. Apple"s fiscal 2021 earnings surged about 65%, while revenue rose 33% on strong demand for its products and services during the pandemic. Its stock has surged nearly 30% this year, bringing the iPhone maker within spitting distance of becoming the world"s first company to cross $3 trillion in market value. Joshi added that he expects Apple"s earnings to grow over the next two to three years. Moody"s, however, said that Apple faces execution risks from short product cycles, the need to adapt to shifting consumer preferences and managing a large and complex supply chain with frequent product upgrades. In October, Apple said that supply chain issues plaguing the industry had cost it $6 billion in sales and the impact could get even worse during the holiday quarter. read more