Apple made Wall Street history as the first company to close with a market value over $3 trillion, the latest sign of Big Tech’s seemingly unstoppable dominance in equity markets.

The iPhone-maker gained 2.3% on Friday, adding to a rally that’s added more than $983 billion to its size this year and leaving it roughly a $500 billion above the next-largest company. Apple’s ascent to the milestone helped the Nasdaq 100 Index to its best-ever first half, driving a broader stock rally that underscored the dominance of tech firms.

The rally has caught many strategists off guard, leading some to question its viability as the U.S. economy faces potentially more Federal Reserve interest-rate hikes. However, investors remain excited about the growth potential of artificial intelligence, and they have also gravitated toward the kind of quality factors that Apple has in spades, including a strong balance sheet, durable revenue streams, and a robust competitive position.