House Financial Services Committee Chairman Spencer Bachus, R-Ala., squares off against state Sen. Scott Beason, a key player in drafting the state's restrictive new immigration law.
Beason -- who has raised less than $75,000 but is supported by the Campaign for Primary Accountability, an anti-incumbent political action committee -- bills himself as providing "true conservative leadership."
Bachus is fending off an insider-trading investigation, The Washington Post first reported a month ago.
CPA has spent more than $200,000 to support Beason, the Post said.
A CPA TV ad says: "Rock the boat. Vote in the March 13 Republican primary."
House Ethics Committee Chairman Jo Bonner, R-Ala., faces a challenge from conservative businessman Dean Young, who has assailed Bonner for voting for the bank bailout in 2008 and for raising the debt ceiling.
CPA has spent $121,000 against Bonner.
Rep. Alan Nunnelee, R-Miss., a Tea Party freshman, is not a CPA target, the Post said, but is being sharply criticized in TV ads by former Eupora, Miss., Mayor Henry Ross, a former judge and prosecutor, for voting to fund Planned Parenthood clinics, raising the debt ceiling and backing "the war on free enterprise."
Rep. Bennie Thompson -- former chairman of the House Homeland Security Committee and the lone Democrat in the Mississippi delegation -- faces Greenville, Miss., Mayor Heather McTeer, running as a progressive.
Thompson has a $1.6 million campaign fund that the Post said would be hard for McTeer's $140,000 to overcome.
Rep. Steven Palazzo, R-Miss., faces Tea Party candidate Ron Vincent, but has a big financial advantage -- $300,000 to Vincent's self-funded $25,000, the Post said.