Last year was an unusually good one for stocks. Not only did markets leap higher, but the gains were evenly felt across every sector. Almost all of the Dow Jones Industrial Average's 30 components improved in 2013, and the top five contributors kicked in just 16% of the Dow's total gains, as compared to 59% in 2012.

The market's mostly steady march led to 23% overall gains, helping leaders like Boeing (NYSE:BA) and 3M (NYSE:MMM) rise by 80% and 50%, respectively.

Yet even through that broad-based, year-long rally, most of the market's gains actually occurred over just a handful of trading days:

Date

Point Gain

Percentage Gain

 Oct. 10 319.7 2.16%
 Jan. 2  308.3 2.35% 
 Dec. 18  291.4 1.84% 
 June 7 203.6 1.35% 
 Oct. 16 203.1 1.34% 
 Dec. 6  194.65  1.23% 
 June 13 183.6 1.22% 

BA Chart

BA data by YCharts.

In the video below, Fool contributor Demitrios Kalogeropoulos discusses the seven trading days that can explain much of the Dow's rise last year. He notes that they represented just 2.7% of all trading days and yet accounted for a massive 50% of the market's annual rise. The takeaway, he argues, is that jumping in and out of stocks is an extremely risky strategy, as missing just one of these days would have been a recipe for underperformance.