The first earnings season since corporate tax cuts was meant to be the markets' saving grace. It hasn't exactly turned out that way.
Matt Maley, equity strategist at Miller Tabak, is trying to get to the bottom of the discrepancy.
"Everybody's been saying, 'Don't worry, the earnings season is going to bail us out.' Sure enough we've had a fabulous earnings season so far," Maley told CNBC's "Trading Nation" on Tuesday. But the season "hasn't moved the S&P at all. In fact, the S&P is actually down slightly since the earnings season began."
Tax cuts have so far delivered a big boost to corporate bottom lines this quarter. Of nearly two-thirds of the S&P 500 that have reported so far, earnings growth has averaged 27 percent in the first quarter, according to Thomson Reuters. That is higher than the initial estimates of 18 percent growth a month ago.
While earnings have soared, the S&P 500 has plateaued. Since the big banks kicked off earnings in mid-April, the S&P 500 has dipped 0.3 percent.
The problem is the stock market was priced to perfection coming into 2018, said Maley. Now, external factors are beginning to intrude on the fundamental bull case.
"Things have changed since January, whether it be talk on trade, whether it be tech regulation, certainly the Fed has started to shrink its balance sheet in a more aggressive way," said Maley. "There's certain things that have made it a little bit tougher when we were priced for perfection like we were back in January."
That has put a ton of pressure on the rest of the earnings season to beat estimates and raise guidance to appease an unimpressed market, according to his analysis.
If the rest of earnings "can't be a catalyst to take the market higher, these other issues I think are going to reassert themselves and that could pose a problem for the market," he said. "The next week or so, maybe 10 days, will be very, very important."
To Gina Sanchez, CEO of Chantico Global, last year's rally put stock valuations at untenable levels, setting the market up for a pullback or two.
"A lot of those downside risks are really starting to get priced into the market," Sanchez told "Trading Nation." "That's healthy. This market has been stretched for some time."
At the market's peak on Jan. 26, the S&P 500's price-to-earnings ratio climbed to 18.6 times forward earnings. Sell-offs in early February and mid-March have pulled its multiple down to around 16.
The market's mindset also explains the disconnect between this earnings season and the S&P 500's subdued reaction, Maley said.
"Last year we had a situation where good news, bad news, no matter what, the market went up. Now not so much. So the psychology is starting to change a little bit," he said.
The S&P 500 is down 0.7 percent so far in 2018. By this time last year, the benchmark index had rallied nearly 7 percent.
Apple could move markets Wednesday after beating profit and revenue growth estimates in its fiscal second quarter. The closely watched metric of iPhone sales was slightly under expectations. The stock was up 4.3 percent in Wedneday's premarket.