Fremont, Calif. -- Shares of Fremont-based Asyst Technologies soared nearly 25% on Wednesday after the manufacturer of chip-making equipment said that it has received an unsolicited takeover offer from Sunnyvale's Aquest Systems. Aquest is offering $6.50 a share, or about $326.3 million. It marks Aquest's second play for the company this year, after earlier teaming with The Gores Group on an offer of between $5-$6 a share. Asyst's board rejected that offer, and said that it is consulting with its financial and legal advisors about the latest overture. Mihir Parikh, Aquest's president and CEO, said he personally has made "significant" investments in Asyst, which are being managed by Riley Investment Management. In a letter to Stephen Schwartz, the chairman, president and CEO of Asyst, Parikh said that his company hopes to "reinitiate conversations with you directly," scheduling a meeting "as soon as possible."