Sale of bonus share after conversion of pvt ltd to ltd co.

My company is private limited company. we have two share holder Mr. A and Mr. B

Mr. A Holding 90 share

Mr. B Holding 10 share

If now i am issueing bonus share to Mr. A and B in the ratio 1:5

Holiding will be

Mr. A - 540share

Mr. B - 60 share

Immidiatly issue of bonus share, we are planning to convert  private limited to limited company and also plan to geting share listed in stock exchange.

If after getting listed in stock exchange , Mr. A is selling share than what will be the acquisition date of his bonus shares

Kindly help me.