SOURCE: FLICKR USER GOTCREDIT.

The proliferation of ETFs has arguably been the best trend for ordinary retail investors during the last decade. Because they are composed of many different stock holdings, ETFs offer investors instant diversification, much like mutual funds. However, ETFs generally offer this diversification with lower fees, more price transparency, and better tax efficiency.

However, you should still learn about an ETF and the niche it represents before you buy a share of it. This is especially important in the fast-moving technology field.

With that in mind, let's look at the top non-levered, non-inverse tech-sector ETF this week. With more than $200 million in assets under management and average-trading volume of 100,000 shares, this ETF outperformed the Nasdaq Composite's slight loss for the trading week ended Dec. 18.

A slightly better week for software
Year to date, it's been a good year for software companies, and specifically, gaming companies (more on this later). Year to date, the Standard and Poor's North American Technology Software Index is up 12% versus the greater Nasdaq, which is up 4%. And this is another week of outperformance for the index, as the passive ETF that represents the index, iShares North American Tech-Software ETF(IGV -0.70%), eked out a small gain of 0.3%, while the Nasdaq fell.

As for the ETF, the fund's expenses are a little high in relation to other iShares offerings, at 0.47%. For example, iShares recently cut expense ratios for seven of its "core" ETFs, bringing down the fee from 0.07% to an extremely cheap 0.03% in its S&P Total Stock Market ETF. As a passive, index-following ETF with more than $1 billion in assets under management, it stands to reason that this fund's fees are comparatively high to other iShares offerings.

How did the index overachieve?
As for the fund's slight gain, it appears to be from Electronic Arts (EA -0.54%), which has a relatively large allocation of 4.5% of the ETF. Shares of the video-gaming company were up 2.7% this week, even including Friday's 3% drop, as "the force" was with the company. Specifically, investors seemed to give the company -- and its blockbuster new game Star Wars Battlefront -- another look, as positive reviews about the movie poured in.

The company recently cut the game's price, with The Wall Street Journal reporting the company saying the initial launch "fell short" of expectations. Investors are apparently hoping positive word-of-mouth from the movie will manifest itself in more game sales; but with a year-to-date gain of nearly 50%, many are able to forgive one bad game.

It was a good week for gaming companies, as Activision Blizzard (ATVI) jumped 3.4%, as well, on news that the company's Destiny: The Taken Kingand Call of Duty: Black Ops III would receive more microtransactions, in-game level-ups, or weapons that allow gamers to more effectively compete -- and the company would be better able to monetize gamers post purchase. The company is roughly 4% of the ETF, so these two gamers account for nearly 9% of the ETF. And Activision has been a strong holding for the ETF, as the stock is up 90% this year.

The ETF's top holding, Microsoft (MSFT -1.84%), also helped with outperformance, as shares of the company also finished up, albeit slightly, on the week. In much the same was as Activision and EA are looking to monetize beyond the initial purchase with in-game transactions, Microsoft has been transitioning its host of software services to a recurrent subscription-based model. Investors have rewarded this large company to the tune of 17% this year, and the company comprises 10% of iShares North American Tech-Software ETF.

If you're in the market for dynamic, high-margin companies that provide the codes and instructions for your favorite games, devices, and apps, but would like diversification, check out iShares North American Tech-Software ETF to see if it fits your investing profile.