Why so many stocks unshortable?

[nic05]

I know the new rule came into play today, but I thought only about 19 big firms would be affected. Today I couldn't short half of the stocks I normally do like URI for etc. Anyone know why?

http://www.nypost.com/seven/07192008/business/sec_eases_short_rule_120574.htm

 

[kickboxers]

Market Makers are on the bid and don't want to buy your short sell.

Quote from nic05:

I know the new rule came into play today, but I thought only about 19 big firms would be affected. Today I couldn't short half of the stocks I normally do like URI for etc. Anyone know why?

http://www.nypost.com/seven/07192008/business/sec_eases_short_rule_120574.htm