The following ratings changes were generated on Friday, Nov. 21.

We've downgraded Aeropostale ( ARO) from buy to hold. Strengths include its robust revenue growth, impressive record of earnings per share growth and compelling growth in net income. However, as a counter to these strengths, we find that the stock has had a generally disappointing performance in the past year.

Revenue rose 21.2% since the same quarter a year ago, outperforming the industry average of 4.3% growth and boosting earnings per share. Aeropostale reported significant EPS improvement in the most recent quarter compared with the same quarter a year ago. The company has demonstrated a pattern of positive EPS growth over the past two years that we feel should continue, suggesting improving business performance. During the past fiscal year, it increased its bottom line by earning $1.80 vs. $1.33 in the prior year. This year, the market expects an improvement in earnings to $2.18. The company has a debt-to-equity ratio of zero, but its quick ratio of 0.4 is very weak and demonstrates a lack of ability to pay short-term obligations. The company's current return on equity greatly increased when compared with its ROE from the same quarter one year prior, a signal of significant strength within the corporation. On the basis of ROE, Aeropostale underpfromed the specialty retail industry but outperformed the S&P 500.

Shares are down 49.1% on the year, apparently dragged down in part by the decline we have seen in the S&P 500. Although its share price is down sharply from a year ago, do not assume that it can now be tagged as cheap and attractive. The reality is that, based on its current price in relation to its earnings, Aeropostale is still more expensive than most of the other companies in its industry.

We've downgraded IBM ( IBM - Get Report) from buy to hold. Strengths include its impressive record of earnings per share growth, compelling growth in net income and revenue growth. However, as a counter to these strengths, we also find weaknesses including generally poor debt management and weak operating cash flow.

IBM has improved earnings per share by 22.0% in the most recent quartercompared to the same quarter a year ago. The company has demonstrated a pattern of positive earnings per share growth over the past two years, which we feel should continue. During the past fiscal year, IBM increased its bottom line by earning $7.24 vs. $6.09 in the prior year. This year, the market expects an improvement in earnings to $8.75. Net income increased by 19.6%, to $2,823 million, compared with the same quarter a year ago, outperforming the S&P 500 but underperforming the computers and peripherals industry average. Net operating cash flow has decreased to $3,739.00 million or 16.55% when compared to the same quarter last year. In addition, when comparing to the industry average, the firm's growth rate is much lower. The debt-to-equity ratio of 1.25 is relatively high when compared with the industry average, suggesting a need for better debt level management. IBM also maintains a poorquick ratio of 0.78, which illustrates the inability to avoid short-term cash problems.

We've downgraded Masimo ( MASI - Get Report), engages in the development, licensing, and marketing of advanced signal processing technologies and products for the noninvasive monitoring of vital signs, from hold to sell, driven by its premium valuation and decline in the stock price during the past year.

Masimo's gross profit margin is currently very high, coming in at 72.8%, having increased from the same quarter the previous year. Regardless of the strong results of the gross profit margin, the net profit margin of 16.7% trails the industry average. Net operating cash flow has significantly increased by 77.45% to $18.32 million when compared with the same quarter last year. In addition, Masimo has also vastly surpassed the industry average cash flow growth rate of 1.54%. The company's debt-to-equity ratio is very low at 0.00 and is currently below that of the industry average, implying very successful management of debt levels. Along with this, the company maintains a quick ratio of 3.07, which clearly demonstrates the ability to cover short-term cash needs.

Shares are off by a sharp 28.38% compared with a year ago, but its decline was actually not as bad as the broader market plunge during the same time frame. One factor that may have helped cushion the fall somewhat was the improvement in the company's earnings per share for the last quarter as compared with the same quarter a year earlier. Although its share price is down sharply from a year ago, do not assume that it can now be tagged as cheap and attractive. Based on its current price in relation to its earnings, MASI is still more expensive than most of the other companies in its industry.

We've downgraded Mindray Medical International ( MR - Get Report), which engages in the development, manufacture and marketing of medical devices, from hold to sell, driven by a generally disappointing historical performance in the stock itself.

Mindray's debt-to-equity ratio of 0.35 is low but is higher than that of the industry average.The company's quick ratio of 1.22 is sturdy. Its gross profit margin is rather high at 54.20%, but it has decreased from the same period last year. The net profit margin of 19.10% trails the industry average. The return on equity has improved slightly when compared with the same quarter one year prior. On the basis of ROE, Mindray underperformed the health care equipment and supplies industry but outperformed the S&P 500.

EPS are up 33.3% in the most recent quarter compared with the same quarter last year. The company has demonstrated a pattern of positive earnings per share growth over the past year, which we feel should continue. During the past fiscal year, it increased its bottom line by earning 70 cents vs. 25 cents in the prior year. This year, the market expects an improvement in earnings to 95 cents. Shares are down 66.1% on the year, underperforming the S&P 500. Although its share price is down sharply from a year ago, do not assume that it can now be tagged as cheap and attractive. Based on its current price in relation to its earnings, Mindray is still more expensive than most of the other companies in its industry.

We've downgraded Petroleo Brasiliero ( PBR - Get Report), which engages in the exploration, exploitation, and production of oil from reservoir wells, shale and other rocks, from buy to hold. Strengths include its robust revenue growth, impressive record of earnings per share growth and compelling growth in net income. However, as a counter to these strengths, we also find weaknesses including a generally disappointing performance in the stock itself, weak operating cash flow and disappointing return on equity.

Revenue leaped 62.9% since the same quarter last year, outperforming the industry average of 30.3% and boosting EPS. The company improved earnings per share by 43.8% in the most recent quarter compared to the same quarter a year ago. Petroleo Brasiliero has demonstrated a pattern of positive earnings per share growth over the past two years, which we feel should continue. During the past fiscal year, it increased its bottom line by earning $2.99 vs. $2.92 in the prior year. This year, the market expects an improvement in earnings to $4.55.

Petroleo Brasiliero's gross profit margin of 39.4% is strong, and its net profit margin of 18.6% compares favorably with the industry average. Net operating cash flow has decreased to $6,464 million, or 10.4% when compared with the same quarter last year. In addition, when comparing the cash generation rate with the industry average, the firm's growth is significantly lower. Shares are down 71.6% on the year, underperforming the S&P 500. Despite the heavy decline in its share price, this stock is still more expensive (when compared to its current earnings) than most other companies in its industry.

Other ratings changes include New York & Co. ( NWY) and Netlogic Microsystems ( NETL), both downgraded from hold to sell.

All ratings changes generated on Nov. 21 are listed below.
Ticker Company Current Change Previous
ANR Alpha Natural Resources HOLD Downgrade BUY
ARO Aeropostale HOLD Downgrade BUY
CSCX Cardiac Science HOLD Downgrade BUY
CV Central Vermont Public Service HOLD Downgrade BUY
DAAT DAC Technologies SELL Downgrade HOLD
DCI Donaldson HOLD Downgrade BUY
FCF First Commonwealth Financial HOLD Downgrade BUY
FNB FNB HOLD Downgrade BUY
FTI FMC Technologies HOLD Downgrade BUY
HCP HCP HOLD Downgrade BUY
HPCO Hallador Petroleum SELL Downgrade HOLD
IBM IBM HOLD Downgrade BUY
IWA Iowa Telecom HOLD Downgrade BUY
MASI Masimo SELL Downgrade HOLD
MR Mindray Medical SELL Downgrade HOLD
MWIV MWI Veterinary Supply HOLD Downgrade BUY
NED Noah Education SELL Initiated
NETL Netlogic Microsystems SELL Downgrade HOLD
NHI National Health Investors HOLD Downgrade BUY
NWY New York & Co. SELL Downgrade HOLD
PAAS Pan American Silver SELL Downgrade HOLD
PBR Petroleo Brasileiro HOLD Downgrade BUY
SWKS Skyworks Solutions HOLD Downgrade BUY
SWS SWS Group HOLD Downgrade BUY
SYK Stryker HOLD Downgrade BUY
TMRK Terremark Worldwide SELL Downgrade HOLD
TWGP Tower Group HOLD Downgrade BUY
USPH U.S. Physical Therapy HOLD Downgrade BUY

Each business day, TheStreet.com Ratings updates its ratings on the stocks it covers. The proprietary ratings model projects a stock's total return potential over a 12-month period, including both price appreciation and dividends. Buy, hold or sell ratings designate how the Ratings group expects these stocks to perform against a general benchmark of the equities market and interest rates.

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For those reasons, we believe a rating alone cannot tell the whole story, and that it should be part of an investor's overall research.

This article was written by a staff member of TheStreet.com Ratings.