Economic security

The Dow may break a 20-year record this week

The recent weakness in the U.S. stock market may mean the end of a couple of major streaks, including one that has stood for more than 20 years.

This week marks the final trading week of the first quarter of 2018, and at current levels it remains a tossup about whether major indexes will extend or end lengthy winning streaks on a quarterly basis.

With two full trading sessions left in the first three months of the year, the Dow Jones Industrial Average (^DJI) is down 1.3% for the quarter. If it closes in negative territory for the period, that will snap a nine-quarter streak of gains, the longest such streak for the blue-chip average since an 11-quarter rally that ended in the third quarter of 1997.

The S&P 500 (^GSPC) is also coming off nine straight quarterly gains, matching a streak that ended in the first quarter of 2015. Currently the S&P 500 is down 0.2% for the quarter, a move it could easily erase over the coming sessions. If it ends positive on the quarter, marking a 10th straight quarterly advance, that will represent the longest such streak since a 14-quarterly rally that ended in the second quarter of 1998.

On a total-return basis, the S&P is down 0.1% over the first quarter. The total-return S&P has also risen for nine straight quarters, but if it goes green for a 10th, that will only match the longest streak since a 10-quarter rally ending in the second quarter of 2015.

The Nasdaq Composite Index (^IXIC) looks safe to extend a notable quarterly streak of its own; it is up 4.3% thus far in the first quarter. However, that only represents its seventh straight quarterly gain, its longest such streak since a 10-quarter rally that ended in 2015.