) --

Vital Images

( VTAL) shares soared in late trades on Wednesday after the Minneapolis-based medical software maker garnered a hefty premium in an acquisition agreement with Japan's Toshiba Medical Systems.

The deal values Vital Images' shares at $18.75 each in cash, a consideration of roughly $273 million. The per-share price represents a 39% premium to the average price of the stock over the past thirty trading days.

The stock was last quoted at $18.62, up 31%, on volume of nearly 100,000, according to

. Based on Wednesday's regular session close at $14.18, the shares were down 8% in the past year.

The next step in the deal is a cash tender offer to shareholders that's expected to begin on May 11.

Toshiba Medical has been a big customer of Vital Images, partnering with the company for more than 10 years. As for the first quarter, Vital Images said its earnings will be "largely in-line" with expectations while revenue is seen coming in "slightly below" consensus estimates because of weakness in Toshiba Medical's business following the earthquake/tsunami disaster in Japan.

The current average estimate of analysts polled by

Thomson Reuters

is for a profit of a penny per share in the March period on revenue of $15.4 million. Of the six analysts covering Vital Images, five had a hold rating on the stock ahead of the buyout news.

Constellation Energy

The potential for a much bigger deal spurred shares of

Constellation Energy

( CEG) higher in extended trades.

The stock leapt 9.3% to $37.50 on volume of around 260,000 after the

Wall Street Journal



(EXC) - Get Exelon Corporation Report

is in talks to acquire Constellation in a deal that could be worth $8.1 billion.


reported the value of the deal at around $7.7 billion in stock, putting the per-share consideration at $38.59 as of Wednesday's close.

Constellation Energy shares have languished for the past year, falling 9.6%; although they have seen a bounce of sorts since scraping a 52-week low of $27.64 in mid-December.

A Baltimore-based energy provider, Constellation Energy is slated to report its fiscal first-quarter results on May 6. The current average estimate of analysts polled by

Thomson Reuters

is for a profit of 96 cents a share in the March period on revenue of $4.12 billion.

Exelon shares dipped 27 cents to $41.22 on late volume of around 45,000.

Akamai Technologies

Shares of

Akamai Technologies

(AKAM) - Get Akamai Technologies, Inc. Report

fell sharply in late trades on Wednesday after the Cambridge, Mass.-based company

edged quarterly profit expectations by a penny

TheStreet Recommends

but spooked investors during its conference call.

The provider of "cloud optimization" services reported normalized earnings of $72.2 million, or 38 cents a share, for the three months ended in March. Revenue rose 15% year-over-year to $276 million in the March quarter. The average estimate of analysts polled by

Thomson Reuters

was for a profit of 37 cents a share in the March period on revenue of $272 million.

For the second quarter ending in June, however, Akamai said it expects normalized earnings of 34 to 37 cents a share with revenue ranging from $270 million to $280 million. Wall Street's current consensus estimate is for a profit of 38 cents a share in the June quarter on revenue of $280.3 million.

The stock fell 11% to $36.51 on after-hours volume of 2.5 million, according to



Online auctioneer


(EBAY) - Get eBay Inc. Report

saw the bid on its shares climb slightly after its quarterly results

topped Wall Street expectations


The e-commerce giant reported an adjusted profit of $619 million, or 47 cents a share, on revenue of $2.55 billion for the three months ended in March. This performance was up from a year-ago equivalent profit of $554 million, or 42 cents a share, and ahead of the average analysts' view for a profit of 46 cents a share on revenue of $2.48 billion.

The shares advanced 7 cents to $34.10 on after-hours volume of more than 3.1 million. That move comes with the stock up 19% since the start of 2011, and nearly 40% in the past year.

Other stocks seeing trading interest after quarterly reports included

Citrix Systems

(CTXS) - Get Citrix Systems, Inc. Report

, which gained 6% after the Fort Lauderdale, Fla. desktop virtualization software company posted a profit of 50 cents a share on revenue of $491 million, topping consensus expectations for earnings of 42 cents a share on revenue of $475.3 million;


(NTRI) - Get Nutrisystem, Inc. Report

, which saw its shares rise nearly 13% after the Fort Washington, Pa.-based weight management company reported a narrower than expected loss and lifted its full-year earnings outlook; and


(FTNT) - Get Fortinet, Inc. (FTNT) Report

, which added almost 8% after the Sunnyvale, Calif.-based network security company

posted better than expected results and announced plans for a two-for-one stock split



Written by Michael Baron in New York.

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

Michael Baron


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

Disclosure: TheStreet's editorial policy prohibits staff editors, reporters and analysts from holding positions in any individual stocks.