Updated from 3:04 p.m. EDTIomega ( IOM) has rejected an unsolicited offer from EMC ( EMC). The San Diego-based maker of storage and network systems said its board on Sunday unanimously decided to turn down EMC's offer to acquire the company for $3.25 a share. The board said it had problems with the bid's valuation and considered its proposed due diligence contingencies overly broad. Iomega said the offer was not superior to a share purchase agreement that it struck with the ExcelStor Group Ltd. in December. The deal called for the Chinese company's parent, Great Wall Technology, to obtain about 60% of the shares in Iomega. Shares of EMC in afternoon trading were down 22 cents, or 1.46%, to $14.81, while shares of Iomega were up 59 cents, or 22.2%, to $3.25. Know What You Own: EMC operates in the data storage industry, and some of the other stocks in its field include Hewlett-Packard ( HPQ), Network Appliance ( NTAP), Sun Microsystems ( JAVA) and IBM ( IBM). These stocks were recently trading at $46.81, $21.47, $15.96 and $113.61, respectively.