Difference between Private Company, Public Company and One Person Company

PRIVATE COMPANIES 
1.Private company requires minimum number of two members and maximum number of 200 members.
2.The liability of each member or shareholders is limited. It means individual assets of the shareholders are not at risk.
3.The company keeps on existing in the eyes of law even in the case of death, insolvency, the bankruptcy of any of its members.
4.The maintenance of index of members is not necessary in case the number of members of the company is less than fifty.
5.Private company needs minimum of two directors, to come into existence and start its operations.
6.There is no minimum capital requirement.
7.In private company there is no need to issue prospectus, as the prohibits any invitation to the public to subscribe for any securities of the company. 
8. It is mandatory for every private company to use the word "private limited" after its name.

PUBLIC COMPANY 
1.The board of the Public company comprises of a minimum number of three members and maximum of 15. The company may appoint more than 15 directors after passing special resolution.
2.Shareholder liability for the loses of the company is limited to their share contribution only. This is what makes it a separate legal entity from its shareholders.
3.A public company has a minimum of seven members and maximum has no limit.
4.The shares of listed public company are easily  transferable between its members and people trading in the stock exchange.
5.A public limited company is not affected by death of one of its shareholders, but the shares are transferred to the next kin of such deceased shareholder and the company continues to run its business as usual.
6.Public companies are strictly regulated and are required to publish their complete financial statements annually. 
7.Public limited companies enjoy an increased ability to raise capital since they can issue shares to the public through the stock market. They can also raise additional capital by issuing debentures and bonds through the same market from the public 
8.The public company should have word limited in its name. 

ONE PERSON COMPANY 
1.It is a company which has only one person as member.
2.It is type of a private company 
3.To incorporate one person company the natural person should be an Indian citizen and  resident in India.
4.Natural person who is an Indian citizen and  resident in India shall be a nominee for the sole member of a One Person Company.
5.A natural person shall not be a member of more than One person Company at any point of time and the said person shall not be a nominee of more than a One Person Company.
6.Where a natural person being  member in One person Company in accordance with this rule becomes a member in another such company by virtue of his being a nominee in that One Person Company, such person shall meet the eligibility criteria specified in sub rule (2) within a period of 180 days.
7.No minor shall become member or nominee of the One Person Company or can hold share with beneficial interest.
8.Such company cannot be incorporated or converted into a company under section 8 of the Act.
9.Such company cannot carry out Non-Banking Financial Investment activities including investment in securities of any body corporate.