Why do companies offer bonus shares?

Say Wipro's stock price was quoting at 1500. Now wipro announces a bonus of 2:1 , i.e for every share, two shares will be additionally given. So logically what do you think should happen? Since at that point of time, there is no real increase in output of the company (i.e no major increase in projected earnings just because a stock is split/ technically no increase in P/E or earnings momentum), the stock should ideally come down to 1/(1+2) = 1/3rd its price. i.e. 500. So i think, Wipro was quoting 1580 at that time and it should have come to around 525 and that is roughly what it is quoting.

Then, Why does a company issue bonus shares?
a) A high denomination share is not easily tradable on the market! ppl would like to trade in lower denominations of good shares. So a stock split helps in increasing the liquidity of the share.

b) Generally, the company thinks that the valuation of the share might be better in the future and it splits the share so that it is tradable. It is a virtuous cycle - lower denomination vs price rise :-). So it is a confidence building measure in the stock by the company.

c) In the short run, the valuation might increase (more speculative than real)! but anyways, stock market is kind of speculative ;-)

d) Another reason (similar to stock buyback) could be the tax benefits. Shareholders can use the capital loss due to reduced stock price to set off the capital gains.