Human capital is a measure of the present value of your client’s future wages, income and salary (net of any future income taxes and expenses). For example, if she is a doctor, lawyer, engineer or even a professor, she has probably invested an enormous amount of time, effort and money to finance her education. That investment will hopefully pay off over many future years of productive labour income in the form of job dividends over the next 10, 20 or even 30 years. Sure, clients can’t really touch, feel or see human capital, but like an oil reserve deep under the sands of Alberta, it will eventually be extracted and so it’s definitely worth something now. ...
Your human capital can be viewed as a hedge against the losses in your financial capital. So, as a 50-, 40-, or especially 30-year old, you should be willing to take more chances with your total portfolio, perhaps even borrow to invest or leverage into the stock market, because you have the ability to mine more human capital if needed.
I'm sorta both (my job is fairly secure, but I'm also a bit entrepreneurial), but time-wise I spend most of my time as a bond. I have taken this into consideration as I have designed my investment portfolio, and definitely take more risks that I would if I were self-employed.
(HT: My Money Blog.)