The Dow Hasn't Done This in a Decade

The Dow Jones Industrial Average (DJIA) and S&P 500 Index (SPX) ended last week in the red, marking their first back-to-back weekly losses since August. What's more, the indexes haven't suffered a three-week losing streak since mid-2016 -- and it's not looking like another weekly loss is in the cards, with stocks at record highs. There have been just six calendar years in history where the Dow and S&P avoided three straight down weeks.

Meanwhile, the CBOE Volatility Index (VIX) -- or the stock market's "fear gauge" -- hasn't ended three straight weeks higher in over a year, on pace for its second-ever calendar year without a three-week win streak. Let's take a closer look at these rare technical feats for the DJIA, SPX, and VIX, and what they could mean for stocks heading into 2018.

Dow Hasn't Done This in a Decade

The DJIA hasn't suffered a three-week losing streak since May 2016 -- 78 weeks ago, according to Schaeffer's Senior Quantitative Analyst Rocky White. The last time the Dow went at least 78 straight weeks without three losses in a row was in 2007. Prior to that, you'd have to go back 20 years for a signal, to just before the 1987 stock market crash. The only other signal -- and the longest -- was in the mid-1950s, when the DJIA went 107 straight weeks without a three-week losing streak.

The last time the blue-chip index went a calendar year without a three-week losing streak was 2006. Prior to that, you'd have to go back to 1989 for a signal. The first signal was in 1909, which preceded a very rough year for the Dow, losing nearly 18% over the next 12 months.

Following these years without three-week losing streaks, the Dow has outperformed at the six-month marker, up 6.66%, on average. That's compared to an anytime average six-month gain of 3.75%, since 1909. However, one year later, the DJIA was up just 0.1%, and was higher just half the time, compared to an average anytime return of 7.17% and a win rate of 65.4%.

Brexit Marked Last Time SPX Suffered 3 Down Weeks

The S&P has gone 73 weeks, since the Brexit brouhaha in June 2016, without a three-week losing streak -- the first time since the streak that ended in early 2014. The longest ever streak without three weekly losses in a row ended in 1996, at 107 weeks.

The last time the S&P 500 Index went a calendar year without a three-week losing streak was 2013 -- the only signal in the past 22 years. There have been just six of these years total, with the first in 1945.

Following these years without three-week losing streaks, the SPX was higher than usual at the three- and six-month markers, averaging gains of 4.79% and 10.34%, respectively. In fact, the index was higher 100% of the time six months after every single calendar year without a three-week losing streak. That's compared to an average six-month gain of 4.38% since 1945, with a win rate under 70%.

VIX Has Done This Just Once

The VIX has now gone 57 weeks without three straight weekly gains, with the last one happening in October 2016, amid pre-election jitters. Only two other times has the VIX gone that long without a three-week winning streak: in the mid-1990s, and during its longest-ever stretch that ended in June 2011.

There's been just one calendar year in history where the VIX didn't end higher three weeks in a row: in 2010. Three months into 2011, the fear gauge was down 1.97%, and sank 10.59% by the middle of the year. However, the index had surged 31.83% by the start of 2012.

2018 Could Start Strong for Stocks

As far as the Dow and SPX are concerned, if the indexes can make it through December without a three-week losing streak, it will be a rare feat indeed. And again, while the sample sizes are small across the board, it's worth noting that both the DJIA and S&P were notably higher than usual three and six months after these years, and the VIX was notably lower at these markers after the lone year without a three-week win streak. If history repeats, it could be a good first half of 2018 for the stock market.