STOCKS CLOSE AT ALL-TIME HIGHS: Here's what you need to know

Stocks hit all-time highs for the first time since May 2015 during an otherwise quiet day on the US economic front.
First, let's head to the scoreboard:
Dow: 18,226.93, +80.2 (+0.4%)
S&P 500: 2,137.16, +7.3, (+0.3%)
Nasdaq: 4,988.64, +31.9, (+0.6%)
WTI crude oil: $44.49, -2.0%
10-year Treasury yield: 1.432%
1. Stocks are at all-time highs. The benchmark S&P 500 index crossed the previous intraday record of 2,134.72, which it touched on May 20, 201