Updated from 1:36 p.m. ESTShares of Perot Systems ( PER) were among technology's losers Tuesday, falling 15.1% after the information technology services company said that it lost its Harvard Pilgrim Health Care contract. Perot Systems said Harvard Pilgrim would replace Perot's transaction processing platform with a new system provided by UnitedHealth Group. The new system, which is expected to be phased in during the next three years, is not expected to have a material impact on Perot's financial results during the next 15 months, it said. According to Perot, Harvard Pilgrim currently represents about 5.5% of Perot's sales and gross profit. Finally, Perot said that it is entitled to a break-up fee associated with the cancellation of the contract. The amount of the fee, which should be finalized during the next several months, is expected to be material and realized in 2006. Shares traded down $2.27 to $12.75. Sina ( SINA) rose 11% after Shanda Interactive Entertainment ( SNDA) disclosed that it acquired 19.5% of Sina through open-market stock purchases. Shanda, which made the disclosure in a regulatory filing, said that it acquired the shares for "strategic investment purposes with the intention of acquiring a substantial ownership position" in Sina. In connection with the investment, Shanda also said that it may "engage in discussions" with Sina to explore the possibility of a merger. In response to Shanda's regulatory filing, Sina adopted a shareholder rights plan, also known as a "poison pill," that would become exercisable if a person or group obtains 10% or more of the company's shares or if Shanda acquires an additional 0.5% of its shares. The triggering of the shareholder rights plan would result in an increase in shares and give rights holders the ability to buy Sina shares at half price. Shares of Sina traded up $2.82 to $28.42. Shanda traded down 19 cents to $29.82.