Barnes & Noble

(BKS) - Get Report

upped its offer to purchase the shares of its dot-com spinoff that it doesn't already own.

Under a plan announced after the close Thursday, the bookstore chain would pay $3.05 for each outstanding share of

Barnes & Noble.com

(BNBN)

. That's up from the $2.50 a share the company

offered in November.

The original offer was the subject of a series of shareholder lawsuits that called the offer inadequate, and charged Barnes & Noble and its subsidiary with breaching their fiduciary responsibilities to other shareholders. As part of the latest offer, the two companies announced that they have settled those suits.

All told, Barnes & Noble is proposing to pay about $150 million for the outstanding shares of Barnes & Noble.com. Under the previous deal, the company estimated it would have paid about $115 million.

The deal is subject to a shareholder vote. However, passage is almost certain given that Barnes & Noble owns about 75% of its dot-com subsidiary's shares and, through preferential stock, controls about 96.6% of Barnes & Noble.com's shareholder votes.

Barnes & Noble bought out partner Bertelsmann's 37% stake in Barnes & Noble.com in September for about $165.4 million in cash and notes, or about $2.80 per share.

Once thought to be the biggest threat to

Amazon.com's

(AMZN) - Get Report

dominance of online retailing, Barnes & Noble.com has lagged far behind its rival. In the first nine months of last year, the company posted $291.4 million in sales, or less than 10% of Amazon's revenue.

While Amazon's stock price is up more than 2800% since it debuted in May 1997, Barnes & Noble.com's has fallen more than 87% since its first day of trading in May 1999.

Separately, Barnes & Noble announced Thursday that its total sales in November and December rose 9.9% to $984.8 million. On a same-store basis, which compares results from like outlets open more than one year, the company's sales increased 3.7% in November and 7.1% in December.

Barnes & Noble.com shares were unchanged in regular trading on Thursday, but rose in after-hours exchanges following the announcement of the new buyout offer. In recent after-hours trading, the company's shares were up 10 cents, or 3.5%, to $3. Shares of parent company Barnes & Noble rose 38 cents, or 1.1%, to $33.98 in regular trading Thursday.

Amazon's shares closed regular trading down $1.66, or 3.2%, to $50.24 and fell another 12 cents, or 0.2%, to $50.12 in after-hours trading.