NEW YORK (

TheStreet

) --

Amazon

(AMZN) - Get Report

was a big winner on Black Friday, reporting that sales of its Kindle e-reader quadrupled from last year.

The e-commerce giant also noted that its Kindle Fire tablet is still the most popular item on its Web site since its launch last month.

Shares of Amazon rose 3.1% to $188 in premarket trading Monday.

AT&T

(T) - Get Report

is considering an offer to divest a significantly larger portion of assets than it had initially expected to salvage its $39 billion merger with

T-Mobile USA

, according to a

Bloomberg

report.

The exact size of the disposals hasn't been determined, said a person familiar with the plan, but they could be as much as 40% of T-Mobile USA's assets,

Bloomberg

reported.

The asset sale is an attempt to address the concerns of the Justice Department, which sued to block the takeover on Aug. 31, and the Federal Communications Commission which last week signaled an attempt to block it,

Bloomberg

said.

AT&T shares rose 1.7% to $27.88 in premarket trading.

Retailers that opened at midnight or earlier on Black Friday

, like

Wal-Mart

(WMT) - Get Report

,

Target

(TGT) - Get Report

,

Macy's

(M) - Get Report

,

Kohl's

(KSS) - Get Report

and

Best Buy

(BBY) - Get Report

, saw on average a 24% boost in their conversion (the number of shoppers that actually made a purchase), according to the NPD Group, a consumer research firm.

In premarket trading, Wal-Mart rose 1.2% to $57.55; Target rose 2% to $52.55; Macy's rose 4.2% to $30.68; Kohl's rose 2% to $52.84; Best Buy rose 3.9% to $26.64.

UnitedHealth

(UNH) - Get Report

affirmed Monday it expects earnings in 2011 of $4.52 to $4.57 a share.

For 2012, the health insurer said it expects earnings of $4.55 to $4.75 a share on revenue of $107 billion to $108 billion. The 2012 outlook excludes certain items.

Analysts expect UnitedHealth to earn $4.76 a share in 2012 on revenue of $108.2 billion.

Ralcorp

(RAH)

, the maker of Raisin Bran cereal and other packaged foods, is expected to post fourth-quarter earnings. The report was originally scheduled for Nov. 8, but was delayed pending the completion of a goodwill impairment analysis of the company's Post cereals business.

Analysts expect Ralcorp to earn $1.39 a share in the fourth quarter on revenue of $1.22 billion.

-- Written by Joseph Woelfel

>To contact the writer of this article, click here:

Joseph Woelfel

>To submit a news tip, send an email to:

tips@thestreet.com

.

Related links:

10 Bank Stocks Bringing Home the Bacon (Mmm... Bacon)

You're Ignoring Taxes and Retiring With Less