If you've been eyeing the recent market dip as a buying opportunity, economist David Rosenberg has a message for you: don't.

Rosenberg, who founded and runs Rosenberg Research & Associates, issued a stark warning on Thursday that the S&P 500's latest slide isn't your typical pullback worth scooping up. "This is probably not a dip you want to buy," he cautioned, pointing to technical damage that suggests the bull run that carried the market through much of 2025 has officially ended.

The Technical Picture Turns Ugly

The trouble started when the S&P 500 breached the 6,550 level, a critical support line that Rosenberg says has "locked in" the rally from April lows as a completed pattern. Translation: the upward momentum is gone, and the market is looking for a floor.

That 6,550 line wasn't just any random number. It comes from Walter Murphy, a veteran market technician formerly with Merrill Lynch and currently at Walter Murphy Global Advisors. Murphy is known for his expertise in Elliott Wave Principle and identifying those pivotal price levels that determine whether markets keep climbing or start tumbling. By breaking through Murphy's "line in the sand," the market has shifted from a "buy the dip" environment to something more defensive, according to Rosenberg.

The bearish setup actually began earlier in the week. On Monday, the S&P 500 slipped below its 50-day moving average for the first time in months, as reported by Saxo Bank. For market technicians, the 50-day moving average is a key gauge of near-term health. Losing that support was the first crack in the bullish case, and the bulls couldn't reclaim it before things got worse.

How Far Could It Fall?

Rosenberg is forecasting what he calls a "garden-variety" retracement of 50%, which would pull the S&P 500 back to around 5,900. That's essentially where the index started the year. We're talking about a decline of more than 10% from current valuations, wiping out months of gains for anyone who's been holding steady.

With both the 50-day moving average break and Murphy's support level violated, Rosenberg's analysis points to further downside ahead. Investors hoping for a quick bounce might instead face a prolonged slide as the market searches for solid ground near its yearly starting point.

Jobs Report Accelerates The Selloff

The benchmark indices had actually started Thursday with gains before reversing sharply following September's jobs report. The S&P 500 closed down 1.56% at 6,538.76 points.

The SPDR S&P 500 ETF Trust (SPY) and Invesco QQQ Trust ETF (QQQ), which track the S&P 500 and Nasdaq 100 respectively, both took it on the chin Thursday. SPY dropped 1.52% to $652.53, while QQQ fell harder at 2.37% to $585.67.

Futures for the S&P 500, Nasdaq 100, and Dow Jones were trading higher on Friday morning, attempting to recover from Thursday's sharp selloff. Whether that represents a genuine bounce or just a temporary reprieve remains to be seen, especially given Rosenberg's cautionary outlook on where this market might be headed.