Is There A Best Day Of The Week To Buy Stocks?

Investors are constantly looking for ways to deliver a new edge to their portfolio. Whether it be through dividend instruments and growth assets that provide the best compound interest upside, or analytic tools, such as P/E ratio investing, it seems there's always a new approach waiting to be discovered. 

As an investor myself with 15 years of market experience, I can certainly attest to the dramatic urge to implement a novel trading strategy you've just stumbled onto. In truth, cobbling together a platoon of different methodological tools, asset types, and price points (both expensive per-share assets and cheaper ones) is generally the best way forward. It mitigates the risk of any one asset type, market sector, or analytical approach suddenly failing. One important investing mistake that many beginner investors tend to make is known as "anchoring," or doubling down on a particular analytical tool or investment approach that has worked in the past, and crucially, stripping it of its context.

Buying stocks on a certain day of the week is one of these kinds of black-box ways of thinking that can run you into trouble. The bottom line is that there's absolutely no single best day to purchase shares. Though some investors hold this notion and swear by it, it's worth noting that those who do trade religiously on the same day each week don't hold a consensus amongst themselves with regard to which day might be the most advantageous, leading to a scattershot effect. This said, rather than pick a "best" day to invest; do this instead.

Note, day trading and trading on a chosen day are not the same thing. Day traders engage in rapid portfolio movements on a daily basis and look for price pressure that might create crucial swings in value; they look to hold assets for a short period of time, perhaps even for a few minutes, as a price dip makes a reversal and increases their held value enough to sell and start the whole exercise over again.

This isn't the same kind of snapshot of the market that day-of-the-week traders take. Instead of seeking to exploit short-term price movements, they look to invest when the market is primed for maximum gain over a longer period. There's nothing inherently wrong with engaging in day trading on a specific day of the week, however. You might have free time every Monday morning for a session.

Statistically, Wednesdays aggregated between 1980 and February 2024 — as part of a J.P. Morgan study on day-of-the-week investing — led the charge with 53.3% ending on a positive change at the closing bell. The worst positive gain percentage over this study period was Tuesday, clocking in a 51.3% positive change rate. As you can see, the difference between these marks is separated by almost no daylight at all. There's simply no evidence to suggest that buying stocks for the long term in an effort to time the market will yield anything other than missed opportunities to capitalize on individual asset-pricing changes that come on other days.

Another key failure in any approach to trading that prioritizes a single day above the rest is that it doesn't take into consideration what is perhaps the only law of markets: Nothing ever stays the same for long. Sure, one of the most recent bull runs (starting in 2009) lasted for more than 10 years before the pandemic wiped out value across the entire marketplace (temporarily). But the market has been experiencing periods of rapid expansion and dramatic retraction in quick succession for its entire history.

Since 1928, there have been 25 bear trading periods, and 27 bull markets in that same time frame. Moreover, all manner of real-world events can shift stock market behavior (natural disasters, interest rates, and warfare, to name just a few). In a very real sense, the sentiments of traders themselves can help shape a market's curving trend, too. When investors find themselves spooked by something new, they often reduce risk positions and hold their cash a little closer to the vest.

In large volumes, this can upset a prevailing equilibrium behavior and send the market tumbling. Flash crashes, soaring price changes, and everything in between often take place over a minute-by-minute timeline, as well as over long trending months or years. There is just no way to truly get granular with the stock market, so trying to is a fool's errand and will drive you crazy.

A calm and calculated investor is one that's poised for success. Traders who thrash around in the market are often looking at too many factors or trying to massage one key indicator into a catchall determinant for their positions. Instead, developing a diverse portfolio that utilizes information gained through an abundance of source material and analytical tools can create a better set of conditions for growth.

Because the market consistently gains value over the long term (according to J.P. Morgan's study, there's been a +4,490% increase of the S&P 500 since 1980), it actually doesn't matter when you buy assets, so as long as you're consistently buying them. Indeed, consistent investment is the most important feature in a growing portfolio.

Of course, researching opportunities and investing in great companies is core to the mission of capital appreciation, but beginners won't generally go wrong in simply looking up an ETF or index fund in a sector they like (or a total market option) and clicking buy. It doesn't matter what day you trade, the brass tacks are crystal clear: Buy stocks frequently with the intention of watching their value grow over the long term, and you'll generally be a pretty happy camper.