Treasury Stock Question

Hoping someone can help me out here. At its most basic, I’m asking what motivates some companies to cancel stocks they repurchase and others to keep them as treasury stock? I was just looking at a company that has 20% of its outstanding shares held as treasury shares. I first noticed it because Bloomberg calculates market cap including treasury stock and Thompson doesn’t, so according to to Bloomberg the market cap is 25% greater. That’s quite a difference. Given that treasury stock doesn’t receive dividends or have voting rights, I don’t see why you would count it in market cap, but that’s a side issue. What I’m really wondering is why would a company buy back 20% of its shares and not cancel them? I guess it makes them easier to reissue, but why cancel them in the first place if you think there will be a need to put them back on the market? Incidentally, the company I am looking at has net cash and liquid financial assets worth more than 90% of its market cap, so the probabilty of it every needing to raise capital again is very small.

The number of outstanding shares decreases if a company repurchases its shares, so that affects market cap, etc, just like Thompson does (according to you). The company can’t cancel those shares because somebody owns them. How would you like it if the company says sorry pal, the shares you own have been cancelled and now you own nothing! The comapny, just like anyone else, will have to buy shares from the market.

FYI - this is a Japanese firm. I edited my first post to correct a typo and now I’ve noticed 2 more, so I won’t bother re-editing but where I said why cancel them in the first place if you are going to reissue them, I meant why buy them back. I had thought the reason you’d have some treasury stock on hand was if you wanted to issue stock options to staff or warrants etc. 20% is exceptional though. Perhaps it’s just an anomoly with this company. I was thinking it could be some sort of anti-takeover device too. Does that sound plausible?