Sybari, which is not yet profitable, has more modest aspirations. The firm filed its S-1 form with the US Securities and Exchange Commission on Friday, saying it hopes to raise $57.5m in the offering.

The company’s flagship software, Antigen, provides virus scanning for Exchange and Lotus Notes messaging servers. More recently, versions for Microsoft’s SharePoint and Live Communications Server, as well as SMTP gateways, have been released.

Sybari lost $400,000 last year, compared to a loss of $2.5m a year earlier, on revenue that was up about 23% on 2002 at $38.3m. In 2003, 48% of its revenue came from outside North America. The firm had about $10m in the bank at the end of 2003.

Sybari is unusual in that it does not create its own virus definitions or scanning engines. Customers choose multiple AV packages from Sybari’s partners: Sophos, Computer Associates, Kaspersky Labs, VirusBuster and Norman.

The idea is that anti-virus firms are unpredictable in their response times to new malware outbreaks and companies can manage their risk more effectively by having two or more scanners, with Antigen tying them together.

The firm has recently also got into the spam filtering market, with some in-house software and partnerships with MailFilters and Commtouch (which is currently fighting off a Nasdaq de-listing, see separate story).

The company lists Microsoft’s potential entry into the marketplace as a risk factor. The AV industry is currently waiting with baited breath to see how Microsoft will use the AV technology it acquired when it bought GeCAD Software last year.