FWIW, This same type of event DID demotivate me and a lot of my co-workers who were early employees at a startup (now 1000+ person company). The company raised a round and the founders sold off some of their shares. We knew because they bought nice cars/houses after the event. Our shares got diluted.
From our perspective, it seemed like a slight vote of no confidence in the company and a little unfair to us that we didn't get the chance to sell shares whereas they did. You lose a bit of that "we're in this together" vibe that makes it organically motivating to work at a place.
Just my 2c, but consider arranging a situation where employees can sell up to a percentage of their options as well. A small percentage makes the eventual payoff palpable and will reduce resentment. You'll likely need to sustain the high levels of motivation for your fast-growing startup to continue it's success.
From our perspective, it seemed like a slight vote of no confidence in the company and a little unfair to us that we didn't get the chance to sell shares whereas they did. You lose a bit of that "we're in this together" vibe that makes it organically motivating to work at a place.
Just my 2c, but consider arranging a situation where employees can sell up to a percentage of their options as well. A small percentage makes the eventual payoff palpable and will reduce resentment. You'll likely need to sustain the high levels of motivation for your fast-growing startup to continue it's success.