Whats is the difference between the definition of concept of control,in accordance to IFRS - 10 and IAS - 27?

The new definition of concept of control as per IFRS10 has a greater focus on "which investor has power over an investee's activities" rather than 'who has the majority of the voting rights".

Thus, it seeks to look more into substance over form as it appears from a prima-facie observation.

More judgement would be required now to determine whether an investor has control - to be determined on a case-to-case basis.

A thorough reading of the below mentioned definitions would make the concept easy to understand-

NEW - As per IFRS10 (Consolidated Financial Statements) -

An investor must possess all of the following elements to be deemed to control an investee:

• Power over the investee, which is described as having existing rights that give the current ability to direct the activities of the investee that significantly affect the investee's returns (such activities are referred to as the 'relevant activities')
• Exposure, or rights, to variable returns from its involvement with the investee
• Ability to exert power over the investee to affect the amount of the investor's returns

NOW STANDS REPLACED  - As per IAS27 (Consolidated and Separate Financial Statements) - 

Control is presumed when the parent acquires more than half of the voting rights of the entity. Even when more than one half of the voting rights is not acquired, control may be evidenced by power: [IAS27.13]

• over more than one half of the voting rights by virtue of an agreement with other investors, or
• to govern the financial and operating policies of the entity under a statute or an agreement; or
• to appoint or remove the majority of the members of the board of directors; or
• to cast the majority of votes at a meeting of the board of directors.