NEW YORK (AP) _ Stocks that have been moving substantially or trading heavily today on the New York Stock Exchange, Nasdaq Stock Market, and American Stock Exchange.

NYSE

Ziff-Davis, up 4 7/8 at 20 3/4

The stock rallied again amid news of the media company's plan to hold an initial public offering of stock in its online operation, ZDNet Group. Ziff-Davis, a New York-based publisher of computer magazines, filed for the $115 million offering on Tuesday.

Sotheby's Holdings, up 4 1/2 at 38

A group including investor Ronald Baron lifted its stake in the auction house to 57.3 percent, according to a new SEC filing. The group bought 571,400 common shares between Dec. 7 and Dec. 22 at prices ranging from $24 to $30.81 per share. Sotheby's is based in Bloomfield Hills, Mich.

Playboy Enterprises class B, up 2 at 21 5/8

Playboy Enterprises class A, up 1 7/8 at 19 3/8

The stocks rose for a second day after CEO Christie Hefner stressed Playboy's online business in an interview on CNBC. Later Wednesday, Playboy issued a statement downplaying her comment that the business could be brought public.

NASDAQ

Delia's, up 7 1/4 at 18 1/8

The company announced that earlier this week it opened its online store on the Yahoo! Shopping service. Delia's, a New York-based retailer of apparel for girls and young women, also said it has formed an alliance with Film.com to create a teen movie section on Delia's www.gURL.com Web site.

Audiohighway.com, up 4 1/8 at 13 1/8

The Internet information and entertainment company raised $12.4 million in an initial public offering of 2.2 million units. For the $6.50 offering price, investors were given one share of stock and a warrant to buy an additional share for $9.75. Audiohighway.com is based in Cupertino, Calif.