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.

While the ratings model is quantitative, it uses both subjective and objective elements. For instance, subjective elements include expected equities market returns, future interest rates, implied industry outlook and company earnings forecasts. Objective elements include volatility of past operating revenue, financial strength and company cash flows.

However, the rating does not incorporate all of the factors that can alter a stock's performance. For example, it doesn't always factor in recent corporate or industry events that could affect the stock price, nor does it include recent technology developments and competitive dynamics that may affect the company.

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.

The following ratings changes were generated on June 13.

Minerals Technologies ( MTX - Get Report), which develops, produces and markets a range of specialty mineral, mineral-based and synthetic mineral products worldwide, has been upgraded to buy. Minerals Technologies' revenue growth has slightly outpaced the industry average of 4.9%. Minerals Technologies 'debt-to-equity ratio is very low at 0.18 and is currently below that of the industry average, implying that there has been very successful management of debt levels. To add to this, Minerals Technologies has a quick ratio of 1.91, which demonstrates the ability of the company to cover short-term liquidity needs.

The net income growth from the same quarter one year ago has greatly exceeded that of the S&P 500, but is less than that of the chemicals industry average. The net income increased by 59.0% when compared to the same quarter one year prior, rising from $10.82 million to $17.21 million. Mineral Technologies has improved earnings per share by 35.4% in the most recent quarter compared to the same quarter a year ago. This company has reported somewhat volatile earnings recently. But we feel it is poised for EPS growth in the coming year. During the past fiscal year, Mineral Technologies swung to a loss, reporting -$1.35 a share, vs. $2.62 a share in the prior year. This year, the market expects an improvement in earnings ($3.75 a share vs. -$1.35 a share). Mineral Technologies had been rated a hold since November 2007.

Film studio Lions Gate Entertainment ( LGF) has been upgraded to hold. Lions Gate's very impressive revenue growth greatly exceeded the industry average of 6.2%. Since the same quarter one year prior, revenue leaped by 54.3%. The net income increased by 19.3% when compared to the same quarter one year prior, going from $25.02 million to $29.84 million. The gross profit margin for Lions Gate is rather high; currently it is at 67.90%. Despite the high profit margin, it has decreased significantly from the same period last year. Despite the mixed results of the gross profit margin, the net profit margin of 5.80% trails the industry average.

The debt-to-equity ratio is very high at 5.27 and currently higher than the industry average, implying that there is very poor management of debt levels within the company. Return on equity has greatly decreased when compared to its ROE from the same quarter one year prior. This is a signal of major weakness within the corporation. Compared to other companies in the media industry and the overall market, Lions Gate's return on equity significantly trails that of both the industry average and the S&P 500. Lions Gate had been rated a sell since August 2007.

KBW ( KBW) and its subsidiaries operate in the financial services industry in the U.S. and Europe and has been upgraded to hold. The 0.37 debt-to-equity ratio is low and is below the industry average, implying that there has been successful management of debt levels. Despite the weak revenue results, KBW has outperformed against the industry average of 47.5%. Since the same quarter one year prior, revenue fell by 26.1%. Weakness in the company's revenue seems to have hurt the bottom line, decreasing earnings per share. KBW has experienced a steep decline in earnings per share in the most recent quarter in comparison to its performance from the same quarter a year ago.

During the past fiscal year, KBW reported lower earnings of 86 cents a share, vs. 87 cents a share in the prior year. For the next year, the market is expecting a contraction of 9.3% in earnings (78 cents a share, vs. 86 cents a share). The net income has significantly decreased by 197.1% when compared to the same quarter one year ago, falling from $7.72 million to -$7.50 million. KBW had been rated a sell since March 2008.

James River Coal ( JRCC), a coal miner in eastern Kentucky and southern Indiana, has been upgraded to hold. James River Coal's revenue growth trails the industry average of 29.6%. Since the same quarter one year prior, revenue slightly increased by 4.3%. James River Coal's share price has jumped by 267.55%, exceeding the performance of the broader market during that same time frame. The company has reported a trend of declining earnings per share over the past two years. However, the consensus estimate suggests that this trend should reverse in the coming year. During the past fiscal year, James River reported poor results of -$3.27 a share, vs. -$1.65 a share in the prior year. This year, the market expects an improvement in earnings (95 cents a share, vs. -$3.27 a share).

The gross profit margin for James River is currently extremely low, coming in at 9.00%. It has decreased from the same quarter the previous year. Along with this, the net profit margin of -12.10% is significantly below that of the industry average. Net operating cash flow has significantly decreased to -$1.03 million or 112.40% when compared to the same quarter last year. James River Coal had been rated a sell since June 2006.

Continental Resources ( CLR - Get Report), an independent crude oil and natural gas exploration and production company, has been rated a hold. Powered by its strong earnings growth of 62.50% and other important driving factors, this stock has surged by 343% over the past year. Continental Resources' very impressive revenue growth greatly exceeded the industry average of 29.6%. Since the same quarter one year prior, revenue leaped by 88%.

During the past fiscal year, Continental Resources reported lower earnings of 16 cents a share, vs. $1.50 a share in the prior year. This year, the market expects an improvement in earnings ($2.88 a share, vs. 16 cents a share). Return on equity has greatly decreased when compared to its ROE from the same quarter one year prior. This is a signal of major weakness within the corporation. Continental has not previously been rated.

Additional ratings changes are listed below.

Ticker Company Name Change New Rating Former Rating
CELG Celgene Downgrade Sell Hold
CLR Continental Resources Initiated Hold
DXPE DXP Enterprises Upgrade Buy Hold
HF HFF Initiated Sell
JRCC James River Coal Upgrade Hold Sell
KBW KBW Upgrade Hold Sell
LGF Lions Gate Entertainment Upgrade Hold Sell
MTX Minerals Technologies Upgrade Buy Hold
NSSC Napco Security Systems Downgrade Hold Buy
NWLIA National Western Life Upgrade Buy Hold
PODD Insulet Initiated Sell
VCGH VCG Holding Downgrade Hold Buy
YTEC Yucheng Technologies Initiated Hold

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