I think the answer to the ‘what % of companies you look at do you invest in’ is a derivative of ‘what are you trying to achieve with your investment dollars’.
in my case I am mainly interested in under valued, solid businesses, with strong past history, strong Management and strong Balance Sheets that pay decent franked dividends. In the main, these will be found in the smaller market caps where volume is thinner which precludes many institutional investors and analyst coverage is sparse. I have 20 in my portfolio and you have to kick a lot of rocks to flip a diamond, but using screeners certainly helps to eliminate the unwanted.
but hey, my approach is tied to my age. I am not looking to shoot the lights out and preservation of what I have is more important than grabbing the tail of the next big tiger.
How picky are you when it comes to investing? What percentage of the companies you look at do you ultimately end up investing in? When I was learning about realestate investing, I took the mantra "less than 5% of properties are investment grade" and have applied it to my stock investing but I am curious how others think of this.