Maybe big, round numbers do matter after all.

Traders like to say milestones on the 30-stock Dow are meaningless and are only closely tracked by retail investors and the media. Yet the benchmark index’s struggle to keep its head above the 13000 threshold, and other similar struggles, suggest that perhaps these landmark levels do matter.

“I think the numbers must mean something to somebody because there is this hesitation that doesn’t seem to correlate with any news item or development of any kind,” said John Prestbo, editor and executive director of CME Group’s (CME) Dow Jones Indexes. "I think the common factor is people’s fascination with round numbers."

Dow 13000 Resistance

Wall Street displayed some serious hesitation surrounding the Dow’s latest milestone.

Bullish investors helped nudge the blue chips beyond 13000 on February 21, marking the first intraday breach of this level since May 2008. However, the Dow failed to close above 13000 that day thanks to a last-minute slide.

After flirting with 13000 the next two sessions, the Dow crossed it again on both Friday and Monday, but closed in the red even as its peers, the S&P 500 and Nasdaq Composite, advanced steadily.

On Tuesday, the blue chips managed to cross the 13000 mark an additional eight times intraday, and eventually closed at 13005.12.

“Just from the observer’s point of view there seems to be a little resistance there,” said Prestbo, who wrote The Market’s Measure: An Illustrated History of America Told Through the Dow Jones Industrial Average.

Historical Precedence

Prestbo also pointed to the long struggle behind the Dow’s push to cross 1000 decades ago.

While the index climbed into four-digit territory for the first time in January and February of 1966, it faded and didn’t return again until 1972 and 1976. Yet each of those Dow 1000 attempts failed and it didn’t manage to stay above that pivotal level until December 1982.

Of course, there can be a number of other explanations for the hesitation around round numbers.

For example, Tuesday investors were grappling with mixed signals on the U.S. recovery, including the strongest consumer confidence reading in a year, but the worst reading on durable goods orders since the depths of the Great Recession in January 2009. 

Americans Love Round Numbers

Still, it would only make sense for investors to at least subconsciously watch these round numbers on the universal Dow.

After all, Americans obsess over landmark numbers in other parts of life, such as anniversaries and birthdays. The sports world tends to be fascinated by round numbers, like hitting for a .300 batting average in baseball, scoring 40 goals in hockey scorer and posting a 50-point basketball performance.

“People for millennia have made markers to measure distance and to measure movement of different kinds. I think it’s just built into our DNA," said Prestbo. 

It’s also probably unfair to solely blame financial newspapers and cable networks for the focus on key thresholds. The media tends to reflect what people think, said Prestbo, a former editor and reporter at The Wall Street Journal.

“Everyone looks at the odometer on the car when it goes over 25,000 miles. Unlike the odometer, the Dow doesn’t keep chugging no matter what. It can go both ways,” said Prestbo.

Follow Matt Egan on Twitter @MattMEgan5