As

AT&T

(T) - Get Report

prepares for its self-imposed

breakup, the company said Wednesday that it will hang onto about 6% of

AT&T Wireless

(AWE)

, instead of distributing its entire stake.

The move underscores how dismally wireless stocks have performed in the past year, and how AT&T the parent hopes to reap any gains the wireless unit might make later this year if sentiment improves.

The largest telecom company in the U.S. also announced that the exchange of AT&T Wireless stock to AT&T shareholders

will be delayed by a month, until early April. This delay won't have any effect on AT&T's plans to cut its wireless unit loose this summer. (Since last April, AT&T Wireless has traded as a tracking stock.)

Awe-ful
Wireless stocks' yearlong plunge

Currently, AT&T owns about 65% of AT&T Wireless, the third-largest wireless service provider in the U.S. By retaining 6% of its stake, or about 150 million shares valued at around $3 billion, the company "believes

AT&T Wireless stock is undervalued," says Frank Marsala, an analyst at

ING Barings

. He rates AT&T Wireless a buy, and his firm has done no underwriting for the company.

Originally, AT&T planned to distribute its entire holding. When the split occurs, AT&T will offer its shareholders the chance to exchange shares in the parent for shares (the ratio has yet to be disclosed) of AT&T Wireless. That exchange offer will serve as a de facto buyback of AT&T shares by reducing the number outstanding and "firm up who wants to own which stock," Marsala adds.

A transmission glitch is the cause of the exchange offer's postponement. An undetected electronic file transfer error omitted a section of the company's March 2000 filing with the

Securities and Exchange Commission

, the company said. The extra month gives AT&T time to get its filings in order.

Shares of AT&T Wireless fell $1.47, or 6%, to $21.54 in early Wednesday trading. They are down 38% from their 52-week high.