((Sen. Scott Brown's support for financial reform bill included in this update.)

NEW YORK (

TheStreet

) --

Aon Corp.

(AON) - Get Report

was among the decliners of the financial sector Monday after the company announced a $4.9 billion deal to acquire

Hewitt Associates

( HEW).

Aon said it will buy Hewitt Associates

, a human resources consulting and outsourcing company, for $50 a share, or $4.9 billion in cash and stock. Aon said the deal will save $355 million annually beginning in 2013. The insurance broker said it plans to integrate Hewitt with its existing Aon Consulting operations under the newly created Aon Hewitt brand.

Shares of Aon dropped by $2.68, or 7%, to $35.66. On the other hand, Hewitt shares jumped by $11.46, or 32.4%, to $46.86.

Elsewhere, most U.S. bank stocks are trading mixed as the second-quarter earnings reporting season kicks off. Among the decliners Monday,

Goldman Sachs

(GS) - Get Report

is down 0.8% to $137,

Morgan Stanley

(MS) - Get Report

fell 0.7% to $24.53, and

Wells Fargo

(WFC) - Get Report

slipped 0.3% to $26.93.

On the positive side,

Citigroup

(C) - Get Report

shares rose 1.5% to $4.10,

JPMorgan Chase

(JPM) - Get Report

is higher by 0.8% to $39.15, and

Bank of America

(BAC) - Get Report

climbed 0.5% to $15.19.

JPMorgan will be the first of the big banks to report earnings on Thursday, and analysts are looking for a second-quarter profit of 71 cents a share on revenue of $25.96 billion. Citigroup and Bank of America are slated to report before the start of trading Friday. Citigroup should record a second-quarter profit of 5 cents a share on revenue of $22.35 billion, according to Thomson Reuters, while Bank of America is expected to notch a profit of 21 cents a share on revenue of $29.69 billion.

Goldman Sachs, Wells Fargo, and Morgan Stanley are scheduled to report quarterly results next week, along with several other financial companies including

American Express

(AXP) - Get Report

,

Bank of New York Mellon

(BK) - Get Report

,

Northern Trust

(NTRS) - Get Report

,

U.S. Bancorp

(USB) - Get Report

, and

E*Trade Financial

(ETFC) - Get Report

.

Bank stocks had little reaction to Sen. Scott Brown's (R., Mass.) decision to support the financial reform bill after the $19 billion tax on large financial institutions was stripped from the reconciled version of the legislation.

"While it isn't perfect, I expect to support the bill when it comes up for a vote,"

Brown said in a statement

Monday afternoon. "That doesn't mean our work is done. Further reforms are still needed to address the government's role in the financial crisis."

Brown specifically targeted the way

Fannie Mae

(FNMA.OB)

and

Freddie Mac

(FMCC.OB)

, which were delisted from the

New York Stock Exchange

last week, operate. Both stocks were rallying Monday after regulators said they would try to recover some of Fannie's and Freddie's losses.

On Monday, the Federal Housing Finance Agency said it has issued 64 subpoenas to various entities, seeking documents related to private-label mortgage-backed securities (PLS) in which the two enterprises invested to determine whether sellers of those securities made any false statements or omissions. This comes after Fannie and Freddie, before and during conservatorship by the FHFA, sought to assess and enforce their rights as investors in PLS, in an effort to recoup losses suffered in connection with their portfolios, the FHFA said.

Fannie Mae shares were surging by 30.7% to 35 cents, and Freddie Mac shares were up 21.7% to 41 cents.

-- Written by Robert Holmes in Boston

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