When there is nothing left to base your permabullish stance on (earnings collapsing, top-line misses, end of surprise factor from ECB/Fed, and sentiment uber-bullish) there is always 'career-risk'. The high-beta performance chase - the need to reach for high-beta names/sectors/indices in the hope that if the market keeps ripping, your performance is levered and you don't lose your job - has been proffered by many 'strategists' for their optimistic short-term projections and year-end targets for the S&P. The problem with this thesis is that it already happened - and dramatically! Since Draghi uttered his magical words, the high-beta Russell 2000's P/E has soared relative to the other major indices. Just as it did during the LTRO exuberance, RTY has seen its P/E surge more than 2x more than the Dow (and reached an epic 9x above the Dow - at 22x Forward earnings on Friday). Since then, the beta-chase has actually decelerated, so either the chase is over, or PMs see 'flatter' as the new 'killing it'.
Forward P/E ratios for the major US equity indices (upper pane) and the difference (lower pane) between the Russell 2000 (higher beta) and the Dow in terms of Fwd P/E...
As an FYI - a 10x spread between Russell 2000 and Dow Fwd P/E has been a notable 'peak' valuation spread in the past 5 years.