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From |
"Alper [iso-8859-9] Sönmez" <salper@metu.edu.tr> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
st: calculate concentration ratio of four firms |

Date |
Sun, 27 Dec 2009 16:42:54 +0200 (EET) |

Hi, I want to calculate the first four firms share in each industry at time t (HHI4 or CH4). I calculated the shares but i cannot sum first four firms shares in each industry at time t. I tried egen and gen commands with several functions but they were not worked Also i did not find any solution or material from stata books and online resources I have an Unbalanced firm level panel data with variables id, years(t) 2003-2006, and 2digitsectors(Sector)and it is in long form The problem: I calculated 1stly, total sales of industry j at time t (Yjt) 2ndly, share of a firm i in industry j (sales of firm i/Yjt)*100=a 3rd a^2 for each firm at time t 4 step is problematic: I can not calculate shares of first four firms in sector j at time t like this max(a+a+a+a) by (sector year) and write this value for firms in these sector and year Please help me, in advance thanks, -- Alper Sönmez ODTÜ/METU ÝÝBF Ýktisat Bölümü/FEAS Department of Economics Ankara Türkiye Tel/Phone:0312 210 30 77 Fax: 0312 210 79 64 * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

**Follow-Ups**:**Re: st: calculate concentration ratio of four firms***From:*Charles Koss <hqtiger@gmail.com>

**Re: st: calculate concentration ratio of four firms***From:*"Martin Weiss" <Martin.Weiss1@gmx.de>

**Re: st: calculate concentration ratio of four firms***From:*"Martin Weiss" <Martin.Weiss1@gmx.de>

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