Five of six

PowerShares

exchange traded funds received initial ratings of "buy" from TheStreet.com Ratings, helped by holdings of commodities companies that stand to benefit from a global economic recovery.

The

PowerShares Global Progressive Transportation Portfolio

( PTRP), which was awarded a grade of A, returned 17% in the past year with little volatility. The fund seeks to mirror the price and yield performance of the Wilder NASDAQ OMX Global Energy Efficient Transport Index, whose key positions are

Westport Innovations

(WPRT) - Get Report

,

Maxwell Technologies

(MXWL) - Get Report

and

Reliance Steel & Aluminum

(RS) - Get Report

.

PowerShares Global Coal Portfolio

( PKOL), also graded A, rose 22% in the 12 months ending Sept. 30, following NASDAQ OMX Global Coal Index stocks such as

Consol Energy

(CNX) - Get Report

,

Massey Energy

( MEE) and

Peabody Energy

(BTU) - Get Report

.

The two PowerShares ETFs starting off at A-minus are

PowerShares Global Steel Portfolio

(PSTL) - Get Report

, tracking NASDAQ OMX Global Steel Index, and

PowerShares Global Agriculture Portfolio

(PAGG)

, guided by the NASDAQ OMX Global Agriculture Index. Those funds climbed 14% and 22%, respectively, for the year under review.

The last newly rated ETF with a "buy"-level rating of B,

PowerShares Global Gold and Precious Metals Portfolio

(PSAU)

popped 39% by hoarding the best-known mining shares of the NASDAQ OMX Global Gold and Precious Metals Index, including

Barrick Gold

(ABX)

,

Newmont Mining

(NEM) - Get Report

,

Goldcorp

(GG)

and

Agnico-Eagle Mines

(AEM) - Get Report

.

Of the six newly rated ETFs, only one wasn't recommended by our quantitative model:

PowerShares Global Biotech Portfolio

(PBTQ)

. It was rated C and slipped 0.4% by tracking the NASDAQ OMX Global Biotechnology Index.

Research Methodology

TheStreet.com Ratings condenses fund performance and risk data into a single composite opinion. That allows for the unbiased identification of funds that have historically done well and those that have underperformed the market. While there is no guarantee of future performance, the ratings provide a solid framework for making informed, timely investment decisions.

For more information, check out an

explanation of our ratings

.

Kevin Baker became the senior financial analyst for TSC Ratings upon the August 2006 acquisition of Weiss Ratings by TheStreet.com, covering mutual funds. He joined the Weiss Group in 1997 as a banking and brokerage analyst. In 1999, he created the Weiss Group's first ratings to gauge the level of risk in U.S. equities. Baker received a B.S. degree in management from Rensselaer Polytechnic Institute and an M.B.A. with a finance specialization from Nova Southeastern University.