The Best (and Worst) Day to Buy Nasdaq Stocks

While the Dow enjoyed its best session since March on Monday, and the S&P 500 Index (SPX) secured a record closing high, the Nasdaq Composite (COMP) added a healthy 72 points, or 1.1%. Looking back at the Nasdaq's best days of late, we discovered a unique pattern emerging: the tech-rich COMP tends to fare particularly well on certain days of the week, and one weekday in particular has been especially lackluster for the index over the last few years.

Analyzing the Nasdaq's last 13 big days -- going by point changes -- all but three occurred on a Monday or Wednesday. The last outlier was on Tuesday, Aug. 22, and prior to that it was Friday, July 7. Before that, you'd have to go all the way back to Sept. 15, 2016, when the COMP advanced nearly 76 points on a Thursday.

This data is underscored when looking at the Nasdaq's one-day gains of at least 1% in 2017. According to Schaeffer's Senior Quantitative Analyst Rocky White, 80% of these big up days occurred on a Monday or Wednesday, at 40% apiece. Only once has the COMP added 1% or more on a Tuesday or Friday in 2017, and we've yet to see a one-day rally of at least 1% on a Thursday this year.

Going back even further, Thursday tends to stand out as the least likely for notable Nasdaq rallies. Since 2016, only 9.3% of the COMP's one-day gains of at least 1% happened on a Thursday -- half that of the second-worst day of Friday, which accounts for just 18.6% of these days. The Nasdaq was most likely to rally on a Wednesday, which accounted for 27.9% of the big days, with Tuesday emerging as the runner-up.

Looking back to 2014, Thursday has also underperformed its fellow weekdays, accounting for just 17.3% of all one-day gains of at least 1%. Once again, Wednesdays were the best, with 27 sessions of at least 1% gains, making up nearly a quarter of all big up days.

In conclusion, if recent history is any indicator, the Nasdaq is most likely to enjoy a huge up day on a Wednesday, with recent Mondays also particularly lucrative for longs. The COMP is least likely to notch a big win on Thursdays, and recent Fridays have been particularly mild, as far as big up moves.