Hillary Clinton's startup tax

It's not a "startup tax". It's a tax on investment income. The capital gains tax break is (supposedly) designed to encourage investment by reducing the tax on income derived from "long term" investments (< 1yr). Currently there is so much investment money available that investors can't find places to invest it all. I'm not sure they need more incentive to invest esp. not at the expense of other taxpayers. When we're awash in cheap oil, does it make sense to give tax breaks to oil companies to "encourage" them to look for more oil?

It's a basic question of fairness: do the Peter Thiels of the world deserve to pay a lower percentage of their income in taxes than the engineers that work for them?

I'm not sure I buy the premise that a few percentage points tax difference in short term angel investments in Silicon Valley will have any effect. For one, angels are aiming for a relatively rare 5-10X (or more) return, so a few percent of 10X is still nothing. Most of these investments are losers. That's just how VC/angel works. Second, I don't think these types of companies really employ anyone. For example, Twitter employs fewer than 4,000 people.

Capital gains taxes apply to most investments. Does this author really believe the wealthy will just put their money under the matress instead of putting it to work?

In which the author informs reality that it is incorrect: "Even a slight change in the risk-return balance — say, the 3.8% which Obamacare quietly laid on top of the current capital-gains — kills companies, as investors and entrepreneurs see the potential upside finally shaved past the tipping point."