"For 2018, the bottom-up EPS estimate (which reflects an aggregation of the median EPS estimates for all of the companies in the index) for the S&P 500 is $146.17. ...[This] will mark a record-high EPS number for the index. However, what is the likelihood that $146.17 will be the final EPS value [and] ...How accurate is the bottom-up EPS estimate one year in advance? Over the past 20 years (1997-2016), the average difference between the bottom-up EPS estimate at the beginning of the year (December 31) and the final EPS number for that same year has been 8.6% ...If we apply [an] average overestimation of 3.7% ([by] excluding the years 2001, 2008, and 2009) to the current 2018 EPS estimate, the final value for 2018 would be $140.69. Based on estimates as of today, EPS of $133.66 or $140.69 in CY 2018 would reflect a record-high for the S&P 500." (Will S&P 500 Report Record-Level EPS in 2018? dated December 8, 2017 by John Butters, Senior Earnings Analyst, with FactSet Research Systems Inc.
https://insight.factset.com/will-sp-500-report-record-level-eps-in-2018