I'm pretty sure Mozilla has a clause in the contract with Yahoo that covers this: http://www.recode.net/2016/7/7/12116296/marissa-mayer-deal-mozilla-yahoo-payme

I'm pretty sure Mozilla has a clause in the contract with Yahoo that covers this: http://www.recode.net/2016/7/7/12116296/marissa-mayer-deal-mozilla-yahoo-payment http://www.recode.net/2016/7/7/12116296/marissa-mayer-deal-m... "According to the change-of-control term, 9.1 in the agreement, Mozilla has the right to leave the partnership if — under its sole discretion and in a certain time period — it did not deem the new partner acceptable. And if it did that, even if it struck another search deal, Yahoo is still obligated to pay out annual revenue guarantees of $375 million."