By way of comparison, the blue-chip Dow Jones industrial average was up 14 percent, while the broader S&P 500 gained 13 percent.
The strong performance of the Tribune/Bloomberg Index can, in part, be attributed to the showing of small-cap companies in general. With only a few exceptions, the bulk of the stocks that make up the Utah index fall into the small-cap category, which by definition are from firms with a market capitalization of $1 billion or less.
Market capitalization is calculated by multiplying the number of shares a company has outstanding by its stock price.
During the first half of this year, small-caps did extremely well, with the Russell 2000 index up 15 percent, said Mark Siddoway of Grandeur Peak Advisors, a mutual fund company based in Salt Lake City.
Siddoway speculated that during the past three to five years, investors have been using more ETFs, or Exchange Traded Funds, to better position their portfolios to a more "macro" exposure to the economy. "As a result, what we've been seeing is money flowing into a [popular] sector and then out again."
But Siddoway noted that a lot of small companies are not held by ETFs. "What I believe is happening is that in the case of small-caps, many are trading more on their fundamentals and less on market movements."
Utah's best-performing company in the first half was the Park City Group, which uses its in-house software and computer systems to help manage customers' inventories. The company's stock was up 153 percent and closed Friday at $7.58 (and was down 3 cents on Monday).
In early May, the Park City Group said revenue grew 21 percent during its recently completed third quarter, and 10 percent for the nine-month period. Net income was $209,294 for the third quarter and $349,827 for the first nine months of the current fiscal year, both records.
"We continued to deliver record results during the quarter, and our growth rate is accelerating," Chairman and CEO Randall K. Fields said in announcing the company's latest quarterly results. "Subscription revenue growth is beginning to see the effect of some of our [newer] larger customers, as they move through the phases of implementation."
Utah's second-best performing stock belonged to Usana Health Sciences, the multilevel marketing company that sells vitamins and nutritional products. Its shares were up 120 percent during the first half of this year.
Usana was followed by Overstock.com, whose shares are up 97 percent since the close of the final day of trading in 2012.
"We're very focused on offering [our customers] great products at great prices," said Jonathan Johnson, Overstock.com's executive vice chairman. He added that effort involves Overstock.com's staff price-checking more than 500,000 items on a weekly basis to ensure the company has the lowest prices on the Internet.
In mid-April, the online discount retailer reported revenue for the first quarter was $312 million, up 19 percent from revenue of $262.4 million posted in the same quarter a year earlier. Gross profit saw a 24 percent year-over-year increase, to $58.9 million.
Of the 23 stocks that make up the index, 14 saw their shares gain in value during 2013's first half. Nine Utah companies saw their share prices decline.
Utah's worst-performing stock belonged to Security National Financial.
The Salt Lake City-based business conglomerate, which operates in three areas life insurance, mortgage banking and mortuary operations was the state's best-performing stock last year, with a 466 percent increase in its share price. Through the first half of this year, though, the company's shares were down 29 percent.
Still, Security National's closing price of $5.92 on Friday was 155 percent higher than its share price a year ago (and was up another 11 cents on Monday).