The U.S. stock market doesn't look like it can keep the summer rally going into the fall, according to the global head of investment strategy at Stifel Wealth and Investment Management.
Hans Olsen told CNBC's "Squawk Box" on Thursday he sees three forces working to conspire against further gains on Wall Street.
First of all, he cited returns. "We hit all the returns I expected that we'd get this year. We've done it through, essentially, in the first eight months," he said.
"When you look at the things that we needed to see in order to sustain the rise in prices," he argued, "it's just not happening."
Secondly is earnings. "We had, what, five consecutive quarters of declining earnings. It looks like next quarter will be another quarter when we see earnings fall as well."
Third on the list was what he called a lack of conviction to the upside due to thin summer trading.
"Basically the entire run has been multiple [expansion] driven. And increasingly these new highs are being hit on very low volume," he said. Even when accounting for the slow summer months, he added volume has been "below average."