A number of big-name dividend stocks were subject to analyst moves before the opening bell today. We highlight the most important changes, along with analyst commentary below.

1. Martin Marietta Materials Upgraded by Longbow Research

Longbow Research upgraded Martin Marietta Materials (MLM ) from Neutral to Buy, with a price target of $188. Shares of Martin Marietta Materials closed at $156.72 yesterday. The company pays an annual dividend of $1.60 (paid quarterly) and has a yield of 1.02%.

2. BlackRock Upgraded by UBS

UBS upgraded BlackRock (BLK ) from Neutral to Buy, with a price target of $350. Shares of BlackRock closed at $295.92 yesterday. The company pays an annual dividend of $8.72 (paid quarterly) and has a yield of 2.95%.

3. Northern Trust Upgraded by UBS

UBS upgraded Northern Trust (NTRS ) from Sell to Neutral, with a price target of $70. Shares of Northern Trust closed at $68.21 yesterday. The company pays an annual dividend of $1.44 (paid quarterly) and has a yield of 2.11%.

4. American International Group Downgraded by FBR Capital

FBR Capital downgraded American International Group (AIG ) from Outperform to Market Perform, with a price target of $63 (from $68). Shares of American International Group closed at $56.92 yesterday. The company pays an annual dividend of $1.12 (paid quarterly) and has a yield of 1.97%.

5. T. Rowe Price Downgraded by UBS

UBS downgraded T. Rowe Price (TROW ) from Buy to Neutral. Shares of T. Rowe Price closed at $68.59 yesterday. The company pays an annual dividend of $2.08 (paid quarterly) and has a yield of 3.03%.