The bull market is turning 4 years old — but yields could crash the party

This bull market has now run for four years, and technology stocks have been the engine behind much of that advance. When investors asked which sectors could keep growing, which earnings could withstand pressure, or where capital should flow, tech was frequently the answer. That leadership has shaped index performance and portfolio returns across the period.

The caution comes from the bond market. Yields compete with equities for investor attention, and when they rise, the appeal of steady fixed-income returns can shift the calculus for stocks — particularly for growth companies whose valuations lean heavily on future earnings. Higher yields can also raise borrowing costs for businesses and consumers, which may weigh on spending and margins over time.

What to watch is whether yields move sharply enough to change the relative attractiveness of equities, and whether tech earnings can continue to justify their premium valuations if financing conditions tighten. Neither outcome is guaranteed, but the interaction between rates and growth leadership is the key variable for the market's next phase.