The rise in bond yields since last month’s market correction could be good news for investors, but the challenge comes in identifying the point at which the trend could be bad for shares. This according to a recent article in The Wall Street Journal.

Whereas bond investors previously thought that tax cuts would boost inflation, the article says they now seem to be anticipating a better long-term economic outlook with lower inflation expectations. However, it says, “huge federal deficits likely to be incurred in the latest U.S. budget come at a time when the jobs market is already tight and there are signs that wage rises may, finally, be accelerating.”

The problem for shareholders watching bond movements is that rising inflation expectations are “good for stocks until they are bad,” says WSJ, citing the example of rising yields triggering the Fed to slow down the economy by raising rates. “Higher yields,” it explains, “will no longer mean higher profits, leaving nothing to offset the hit to valuations that comes with a higher discount rate.”

At what yield level such a “turning point” will materialize is uncertain, according to the article, and “shifts with changing beliefs about the economy.” It concludes that while for years investors have justified buying stocks at high valuations because bonds held no appeal, things are now shifting. “As Treasury yields rise,” it says, “expensive shares will look less attractive—so companies will need the prospect of big rises in profits to maintain their appeal.”