After a sharp run-up in its share price, Apple has won the title of most valuable company of all time.
The tech company started the work week up about 2 percent, continuing a rally that was driven last week by rumors about redesigns in the works for both the iPhone and iPad, the Wall Street Journal reported.
The company was valued at about $621 billion or $662 a share during late afternoon trading, a valuation that tops the 1999 record of $616.3 billion held by Microsoft, the Journal reported.
Microsoft's market cap comparison doesn't account for inflation, which means that Apple is now worth 53 percent more than Exxon Mobil -- the world's second-most valuable company.
The Associated Press points out that PetroChina, China's largest oil company, was briefly valued at $1 trillion when it was first listed on the Shanghai stock exchange, though it never topped $500 billion on the Hong Kong and New York Stock Exchange.
Some analysts have predicted Apple could go even higher, with several firms boosting its price target to over $900.
The iPhone, one of Apple's hallmark products, is undergoing a design overhaul that's been generating buzz and driving the stock price higher. The new design is expected to have a larger screen, a thinner body and work better with more cell phone carriers, analysts told Bloomberg News. Apple introduces the new iPhone Sept. 12.