Hart Capital Management Inc., a Spokane-based investment firm, says the stock value of 15 publicly traded Inland Northwest companies as measured in an overall index it compiles rose nearly 7 percent in the first quarter.

Hart's index uses a methodology similar to that of the Standard & Poor's 500. By comparison, the S&P 500 rose 10 percent in the first quarter. When measuring the 12-month period ending March 31, the Inland Northwest index rose 14 percent, compared with an 11 percent increase by the S&P 500 in that same period, Hart Capital says in its quarterly report.

The top-performing stocks in the Hart Capital Index during the first quarter were Idaho Independent Bank, Clearwater Paper Corp., and Potlatch Corp., with respective increases of 56 percent, 35 percent, and 17 percent.

Coldwater Creek Inc.'s stock performance was the laggard in the Hart index, with its stock plummeting 34 percent for the quarter. Other companies showing declines in stock performance were Hecla Mining Co. and Coeur d'Alene Mines Corp., down 32 percent and 23 percent, respectively.

Meanwhile, Hart Capital also compiles what it calls the Inland Northwest Composite to track the aggregate market value of the same 15 publicly traded companies. Market value, or capitalization, is share price multiplied by the number of outstanding shares.

In the first quarter, the composite here fell $151 million, or 1.3 percent, with declines in market value that included $537 million for Hecla Mining, $503 million for Coeur d'Alene Mines, and $50.5 million for Coldwater Creek.

Hart Capital says the main reason for the discrepancy between the index and composite first-quarter performances is that both Clearwater Paper and Potlatch have become larger contributors to the index as their market capitalizations have grown over the past two quarters.

As a result, those companies' index gains outweighed the declines by Coeur d'Alene Mines and Hecla Mining, which had become smaller contributors to the index over the same period.

At the same time, the gross market capitalizations of the companies in the Hart composite that grew the most in the first quarter didn't offset those that fell, Hart Capital reports.

It says that as of March 31, the composite of the 15 companies was $11.6 billion.

Over the prior 12 months, the composite increased by nearly $700 million, or 6.4 percent, largely due to market cap increases of $592 million, $453 million, and $142 million by Potlatch, Clearwater Paper, and Avista Corp., respectively.

In addition to the companies mentioned, the other companies in the Hart index and composite include Ambassadors Group Inc., Itron Inc. Key Tronic Corp., WTB Financial Corp., Northwest Bancorp., Red Lion Hotels Corp., Intermountain Community Bancorp., and Sterling Financial Corp.