Andrew Burkly of Oppenheimer points out that the underperformance has come even as one of the key concerns for the market—a presumptive rate rise from the Federal Reserve—has been pushed further and further off.
The most conservative forecasts "were looking for multiples to compress because the Fed would be raising rates," Burkly said Monday on CNBC's "Power Lunch."
That is, strategists expected that earnings would look good, but that investors would pay less for each dollar of earnings (that is, a smaller multiple) due to the higher rates.
"What's interesting is that we didn't get the Fed rate hike. We've gotten a little bit of multiple compression, but it's really on the earnings that most strategists missed their mark," due to continued low energy prices, Burkly said.
Read MoreMarket fear rises after Fed non-move
Not only were strategists too bullish, then, but they were too bullish even though an apparently bearish event that they predicted has not yet come to fruition.
While this might be used as an excuse to mock strategists' inaccuracy, it also shows just how important the price of oil is to the S&P 500, given the energy weighting in the index. And with oil in free fall, the already tough task of predicting where stocks will end the year appears to have gotten even harder.