At the end of last year, Golub's forecast for the S&P 500 for 2015 was 2,325, "consistent with 12% potential upside". Of the strategists followed by Business Insider, Golub was tied for most bullish forecast.
But in a note to clients on Monday, Golub lowered his forecast to 2,100, which would see the S&P 500 gain just 2% for the year.
The benchmark index opened at 1,911.75 on Monday; it would need a roughly 10% rally to hit RBC's forecast.
Golub also lowered his S&P 500 earnings forecast to reflect the fact that lower commodity prices and sluggish global growth have eaten into corporate earnings this year.
"The Energy sector has been the largest drag, weighing on buybacks as well," he wrote. "We are adjusting our S&P 500 earnings estimates to reflect these trends. Specifically, we are lowering our 2015 and 2016 EPS forecasts to $120 and $128 from $125 and $135, respectively."
On Sept. 8, Bank of America Merrill Lynch's Savita Subramanian reduced the firm's year-end target on the S&P 500 5% to 2,100 from 2,200 on similar concerns about slow global growth. In an Aug. 28 note, Credit Suisse's Andrew Garthwaite lowered his target to 2,100 from 2,200 citing similar concerns.
One of the big questions this year has been the extent to which weakness in emerging markets, particularly in China, would impact the US economy, company earnings, and the stock market.
"Our longer-term outlook for market trends remains largely intact," Golub wrote. "We believe the market will deliver ~10% annually for the next several years. This will be driven by ~7% EPS growth with the balance from multiple expansion. Our growth and valuation forecasts are each being taken down by approximately 1% to reflect a slowing pace of buybacks and a delayed re-normalization of interest rates."
Year-to-date, the S&P 500 is down 7.5%. And judging from this list of top forecasts from Wall Street, the stock market has been more turbulent than most people expected.