This is an archived article that was published on in 2011, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.

The sell-off in the stock market during the third quarter took its toll on Utah's 27 largest publicly held companies.

The Salt Lake Tribune/Bloomberg Index, made up primarily of companies with market capitalizations of $1 billion or less, declined 17 percent during the first nine months of 2011, with only seven of its 27 companies seeing gains in their share prices during that period.

By way of comparison, the 30 so-called large-cap companies making up the widely followed Dow Jones industrial average saw their average share price decline just under 6 percent, while the broader S&P 500 index posted a 10 percent decline.

Market capitalization is calculated by multiplying the number of shares a company has outstanding by its stock price.

"If you look at the performance of small-cap companies nationwide, all the negative return year-to-date occurred over the past two to three months," said Blake Walker, a portfolio manager at Grandeur Peak Global Advisors, a newly organized Utah investment company that is preparing to launch two mutual funds next week.

Despite the overall decline in The Tribune/Bloomberg Index, there still were a few standouts.

Nu Skin Enterprises, the Provo-based multilevel marketing company, saw its shares gain 34 percent during the first nine months of 2011. It was the best-performing company on The Tribune/Bloombergindex.

"Our [share-price] gain so far this year is the culmination of several years of strong performance and new-product launches," said Ritch Wood, Nu Skin's chief financial officer. "We've been seeing strong sales growth in many of the emerging markets, along with Southeast Asia and mainland China."

Utah's Zagg Inc., which sells protective film coverings to keep electronic devices scratch-and-dent free, was the second-best performer. Its shares were up 30 percent since the first of the year.

"Our biggest milestone so far this year was when we acquired iFrogz," said spokesman Nathan Nelson. The latter continued "to be a fast-growing company and their products have a great presence in Walmart and other major retailers."

The acquisition of iFrogz, which operates as a Zagg subsidiary, added protective cases, headphones and earbuds to Zagg's growing product offerings.

Dynatronics Inc., a maker of medical equipment used by physical therapists, chiropractors and sports medicine practitioners, also performed well. Its shares were up 27 percent during the first nine months of 2011.

Dynatronics had the best-performing shares during the first quarter and first half of this year.

Shares of Schiff Nutrition, which markets vitamins, supplements and sports nutritional products, rose 22 percent. Extra Space Storage, which operates self-storage units across the county, rounded out the top five with a share price gain of 7 percent.

Some of the best-known companies in the state, though, saw their share prices decline in the face of the third-quarter market sell-off brought about by concerns that the nation's economy again was slipping into recession.

Online discount retailer, which goes by, saw its shares decline 44 percent. Headwaters Inc., the South Jordan-based building products company, fell 69 percent as the nation continued to struggle with weakness in the construction industry.

Twitter: @OberbeckBiz