By Gary Gordon of ETF Expert

NEW YORK (

ETF Expert

) -- Prior to 2000, a strong dollar was often synonymous with a strong U.S. economy. Over the last decade, however, greenback strength has often signified a fear of riskier assets (e.g., stocks, commodities, emerging market currencies, etc.).

In 2010, the correlation between stocks and dollars only intensified. When the dollar trended lower, riskier stock assets flourished ... and when the dollar moved higher, stocks limped their way toward the closing bell.

There are other reasons for the "coupling," however. Commodities are priced in the world's reserve currency. It follows that miners/explorers/materials companies may generate larger profit margins when it takes more dollars to pay for "stuff." Consequently, materials-heavy

iShares Emerging Markets

(EEM) - Get Report

had a -.78 correlation coefficient to

PowerShares Dollar Bullish

(UUP) - Get Report

in 2010.

Another reason for the ongoing marriage in 2010 has been the lack of faith in the euro. With the year-long sovereign debt crisis emulating the subprime disaster, every European Union hiccup has destabilized the euro (reinforced the buck.) Not surprisingly, then, the

iShares Europe 350 Index

(IEV) - Get Report

has a startling -.90 coefficient with UUP.

(Note: Remember that correlation coefficients travel between 1.0 and -1.0 such that .70, .80, .90, positive or negative, is deemed exceptionally strong. In contrast, .20, .30, .40, positive or negative, is deemed modest.)

On the flip side, the dollar's effect on U.S. stock assets may be waning. PowerShares Dollar Bullish correlated at .54 with the

S&P 500 SPDR Trust

(SPY) - Get Report

and .61 with the

Dow Jones Diamond Trust

(DIA) - Get Report

. Married? Perhaps... but not quite joined at the hips.

So here's the kicker. Which stock asset classification has had the most casual, least significant relationship with the buck? U.S. micro-caps. Here's how micro-cap stock ETFs --

iShares MicroCap

(IWC) - Get Report

,

First Trust MicroCap

(FDM) - Get Report

and

PowerShares Microcap

(PZI)

-- performed on the year, alongside their correlation coefficients with PowerShares Dollar Bullish.

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Disclosure Statement: ETF Expert is a Web site that makes the world of ETFs easier to understand. Gary Gordon, Pacific Park Financial and/or its clients may hold positions in ETFs, mutual funds and investment assets mentioned. The commentary does not constitute individualized investment advice. The opinions offered are not personalized recommendations to buy, sell or hold securities. At times, issuers of exchange-traded products compensate Pacific Park Financial or its subsidiaries for advertising at the ETF Expert website. ETF Expert content is created independently of any advertising relationships. You may review additional ETF Expert at the site.