So what happens with the other two-thirds? Well that is the part of the startup world that we don’t talk too much about. Sometimes an entrepreneur will take an early exit. They will have raised a small amount of outside money, will still control the company, and will get an offer they can’t refuse and take it. That’s a win for the entrepreneur but not for the VC. But it is a happy outcome for everyone anyway. That’s maybe 10% of the total outcomes. So at least 50% of the outcomes are not a win for the VC or the entrepreneur.

So what happens when things don’t work out? There are generally two scenarios.

The first is the “slog it out” scenario. This one is in many ways the most painful. It means that there is a business that can be built, but it won’t be one that makes the VCs much money, and because it takes so much time and money to “slog it out,” it doesn’t make the entrepreneur much money either. And in many cases, the entrepreneur chooses to leave, and the company has to recruit outside management to operate the business.

In the “slog it out” scenario, the VCs are often left holding the bag. They have a lot invested in the business and have a responsibility to figure out how to get it out. In some cases, the entrepreneur sticks around and slogs it out along with the VCs. I have great admiration for the entrepreneurs I have worked with who have slogged it out. There is very little upside for them in this scenario. Mostly they do it out of a sense of responsibility. These “slog it out” businesses can go on for a long time. I am involved with some that are well into their second decade, and I am afraid that they may be headed into a third decade.

I have heard these kinds of companies called “zombie companies” and “the living dead.” That’s a bit unfair, because there is no way a company can operate for two or three decades without being able to sustain itself. VCs do not keep pouring money into these businesses, maybe they do that for the first five years, but not after that. These “slog it out” companies turn into real companies eventually but just not companies that have the growth trajectories or strategic profiles that make them great acquisitions.

The second scenario is “hit the wall.” In this scenario, the company runs out of cash, and there is no more coming from the investors. The company cannot sustain itself and one of two things happens. There is a fire sale or an acqui-hire, or there is a shutdown.

The fire sale is the preferred outcome, and VCs and entrepreneurs have gotten pretty good at finding homes for the teams in recent years. There is such a vacuum of talent out there that a fire sale can often be arranged just for the talent that a company has assembled. But often the fire sale cannot be arranged, and the company has to be shut down. Again, the responsibility for an orderly shut down often falls onto the VCs to manage. In a shut down, the employees must be notified and paid through the date of the shut down. All required tax payments must be made. Liabilities such as leases and bank borrowings must be managed. In particularly messy situations, a bankruptcy filing is required.

There are two interesting things here that I always think about. The first is that even the very best investors in the VC business only get a hit about 1/3 of the time. That means that they have their share of “slog it outs” and “hit the walls” too. I am certainly in that camp. The second is that we end up spending an incredible amount of time and energy (hopefully not money) on the 2/3 of our investments that don’t work out. When everything goes well, you really don’t need that much from a VC.

Of course, I have added value in all of my winners. But its the ones that don’t work that I have left my blood, sweat, and tears on. And that’s the paradox of being a VC that cares. Which is the only kind of VC you want to work with.

Fred Wilson (@fredwilson) has been a venture capitalist since 1996 and currently serves as managing partner of Union Square Ventures. This is reposted from his personal blog.