The most obvious answer is “growth.” But does the answer change after they have invested in you?
A long time VC who was a Board member of two of my companies told me what investors really want: Predictability. Once you think about it, that becomes obvious. They invested in your company because they saw its growth potential but now what they want and expect is predictability: no surprises! That means you meet ship schedules, project budgets, financial goals, whatever the metric: meet or exceed those targets consistently and you will have investors whose expectations you have met and who will stay out of your strategic and operational hair.
But be careful of the “under promise, over deliver” maxim. Too much of that and you will be accused of “lowballing” or “sandbagging.” Take your pick: neither is good.
So what investors want should be want you as CEO, COO, CXO, director or manager, or staff want: predictability. It’s very hard to predict the future, but then building a successful startup is very, very hard.
So get buy-in on your metrics or in Silicon Valley Lingo, KPIs, then boringly and predictably meet those metrics, again and again.
If you do that you may eventually get to a pleasant surprise, such as a buy-out offer or an investment bank calling because they want to take your company public.