The maker of tools to help companies manage computer systems rose above a new $25.50-a-share cash buyout offer from a strategic bidder that topped a previous agreement with Insight Venture Partners. The shares increased 9.2 percent, the biggest gain since May 9, when Quest said it got alternative buyout proposals after reaching a deal to be acquired by Insight for $23 a share in March. Quest did not name the new bidder. Reuters reported it is Dell Inc., citing people familiar with the matter.