一类公司（在全球市场占主导地位）：
The leaders include Symantec, McAfee (NAI) and Trend Micro - the activity of these companies affects all markets
Symantec
NAI (McAfee)
Trend Micro
Company Annual turnover, $mln
2003 2004
Symantec 1098 1364
McAfee (NAI) 577 597
Trend Micro 382 508
These three companies occupy leading positions in all markets, with a few exceptions (for instance, Trend Micro dominates the Japanese market). Symantec and NAI (McAfee) are North American. Trend Micro is originally a Taiwanese company which was floated on the Japanese stock market. It is currently headquartered in the USA.
第二组（在本国占有较大市场，在其他国家占有率较小，但是每年仍有上百万美元营业额）
The second tier includes companies whose turnover is significantly lower than the leading three. However, these companies still have an annual turnover of tens of millions of dollars:
Sophos
Panda
Computer Associates（CA）
F-Secure
Norman
AhnLab
Kaspersky（注：这个是我给添上去的，Eugene Kaspersky非常谦虚，为了避嫌，Eugene Kaspersky没有把Kaspersky列入名单，只是写了这些：Kaspersky Lab, based in Russia, is also included in this group. However, the company does not disclose financial information.）
Company Annual turnover, $mln
2003 2004
Sophos (UK) 97 116
Panda Software (Spain) * 65 104
Computer Associates (USA) 61 74
F-Secure (Finland) 36 51
Norman (Norway) 23 31
AhnLab (S.Korea) 21 28
*Panda Software is a private company. Financial information given is unaudited
Kaspersky Lab, based in Russia, is also included in this group. However, the company does not disclose financial information.
The majority of second tier companies have a significant presence in their respective domestic markets, but a relatively small presence in foreign markets. For instance, Sophos is most successful in the UK, Panda in Spain, F-Secure in Scandinavian countries etc.
第三组
The third group includes several dozen antivirus companies. The best known include:
Alwil - Awast (the Czech Republic)
Arcabit - MKS (Poland)
Doctor Web - DrWeb (Russia)
ESET - NOD32 (Slovakia)
Frisk Software - F-Prot (Iceland)
GriSoft - AVG (the Czech Republic)
H+BEDV - AntiVir (Germany)
Hauri - VI Robot (South Korea)
SoftWin - BitDefender (Romania)
VirusBuster - VirusBuster (Hungary)
UNA and Stop! (both Ukrainian)
Rising（瑞星） and KingSoft（金山） (China) and others.
The third group also includes UNA and Stop! (both Ukrainian), Rising and KingSoft (China) and others.
The majority of companies in this group do not disclose any financial information. However, some estimates state that annual turnover is around $10 million.
