You can take Yandex out of Russia... but you can not take Russia out of Yandex. Admittedly, the same could probably be said about any other $big_search:$nuclear_power pair. It's just that the other companies either can't or have no reason for exile.

And so I suspect Yandex leaving it's home turf would essentially be a covert invasion of wherever they'd swarm to. Somehow, money tells me UK would be a likely target. Source: worked briefly for an exiled Russian company. Would not repeat.