Assurant ( AIZ) was upgraded at Bank of America/Merrill Lynch to neutral. $60 price target. Company is seeing a pricing overhang easing in Florida, BofA/Merrill said.

Chesapeake Energy ( CHK) was downgraded at Stifel Nicolaus to hold from buy. Valuation call, given low expectations for production growth, Stifel Nicolaus said.

Emcor ( EME) was upgraded at DA Davidson to buy from neutral. Company is leveraged to a recovering nonresidential construction environment, DA Davidson said.

Corning ( GLW) downgraded at Piper Jaffray to neutral from overweight. $14 price target. Company lacks exposure to new product cycle in display.

JB Hunt ( JBHT) was upgraded at Bank of America/Merrill Lynch to buy from neutral. $81 price target. Company offers a strong secular growth story, BofA/Merrill said.

Johnson & Johnson ( JNJ) was upgraded at Goldman Sachs to neutral from sell. Pharma outlook is improving, Goldman said. $95 price target.

Life Technologies ( LIFE) was downgraded to hold at TheStreet Ratings.

Eli Lilly ( LLY) was downgraded at Jefferies to underperform from buy. Estimates were also lowered, given worsening business environment and disappointing R&D productivity, Jefferies said. $40 price target.

L Brands ( LTD) was downgraded at Credit Suisse to neutral from outperform. $64 price target. Comp weakness persists and inventories are building, Credit Suisse said.

Merck ( MRK) was downgraded at Jefferies to hold from buy. Estimates were also decreased on weak business environment and unimpressive cost-cutting initiatives, Jefferies said. $50 price target.

Pharmacyclics ( PCYC) was upgraded at Goldman Sachs to buy from neutral. $170 price target. ibruttinib could generate $7.5 billion of peak annual sales, Goldman said.

Premier Exhibitions ( PRXI) was downgraded to sell at TheStreet Ratings.

Sonoco ( SON) was downgraded at Goldman Sachs to sell from neutral. Company will likely grow slower than its peers over the next few quarters, Goldman said.

Stock Comments / EPS Changes

Calpine ( CPN) estimates, price target were reduced at UBS. Estimates were reduced through 2014. Company lowered its guidance, UBS said. Buy rating and new $22 price target.

Lowe's ( LOW) estimates, target upped at Credit Suisse. Estimates were boosted through 2015. Higher comp sales are driving gross margin expansion. Outperform rating and new $55 price target, Credit Suisse said.

Methanex ( MEOH) estimates, price target were raised at UBS. Shares are now seen reaching $59. Estimates were also increased, as the company is seeing higher reference pricing, UBS said. Buy rating.

Micron ( MU) estimates were increased at Jefferies. Elpida and DRAM ASPs contributing to income and gross margin, Jefferies said. Buy rating and $30 price target.

Micron estimates, price target were increased at UBS. DRAM pricing is moving higher, UBS said. Buy rating and new $23 price target.

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This article was written by a staff member of TheStreet.