The stock market rally is about to crumble, and investors should expect zero upside for equities through the end of the year, Goldman Sachs says

• The impressive year-to-date rally in the stock market is about to crumble, according to Goldman Sachs.
• The bank said the S&P 500 has more downside than upside between now and the end of the year due to high valuations and weak earnings growth.
• "The debt ceiling deadline later this year adds uncertainty to the path for US stocks," Goldman said.

Goldman Sachs is growing more and more skeptical of the impressive year-to-date rally in the stock market, according to a Friday note.

The S&P 500 is up more than 7% year-to-date and eclipsed the all-important 4,000 price level two weeks ago. But according to Goldman, 4,000 is about as far as the S&P 500 is going to go between now and the end of the year.