Among many the bad terms disclosed in the article, IMO this is probably the worst - basically, this right is a license to cash out and torpedo the company within 3 months (just the right amount of time to see how the market reacts to Spotify's first earnings call as a public company..), leaving the other investors (and employee common stock holders!) with greatly devalued stock.

Of course they have a disincentive not to do this: if they did start to sell after 90 days, the stock would start plummeting before they could sell all shares, so the last shares that TPG/Dragoneer sell would be worth much less than the first bucket of shares, but if they do sell it means that things are very, very bad and they'd rather cut their (20% discounted...) losses, and will be much, much better off than the other investors and employees 3 months later.

godspeed Spotify!