[MaulingMonkey]

> I don't see how you can dispute that having a large part of your net worth in a single stock leaves you vulnerable if anything happens to it.

Aye, it's not a diverse investment. Especially if you consider your employment a form of investment.

[zardo]

Don't forget your house, its value is dependent on the local economy, which could be tied to your employer. If you own a house in a town that is largely employed by ACME, and you work there, and you invest your money in ACME, if ACME goes under you lose your job, your retirement savings, and potentially the value of your home.