No. It was pretty evenly divided between the owners. But it is rumored that Arkady got only half of what he was owed legally. Russia and all that, the price to pay for leaving. That was the reason why he made anti-war statements only after the split. Oleg Tinkov made a statement after the invasion and was able to get out with only 5% of the real price of Tinkoff bank. But he has a very successful Plata bank in Mexico and Americas.
Nebius is more concentrated, Yandex is way more spread in what they do.
As I understand, Nebius is tiny compared to Yandex in Russia which has: a search engine, maps, an ad network, a taxi, a bank and contactless smartphone payment system, food delivery, with autonomous delivery robots actually operating in Moscow/SPb and not prototypes, a cloud, Amazon-like services, etc. Nebius has nothing of similar scale.
Yandex robots are driving around Moscow and SPb delivering food to people. Where are Nebius robots? "AI infrastructure" means just that they rent out GPUs they bought for themselves and did not find a use?
Comparing GDP means nothing. Having larger GDP doesn't mean the country is stronger, it is just a number.
Also in this case, you are comparing not the GDP (actually produced goods and services) but a "market cap" which is a virtual number calculated by price of one share multiplied by share count. Yandex shares, I assume, cannot be traded internationally so the number means nothing. Yandex has a public report where one can find out their revenue.
Companies are valued on their potential. Yandex growth was 70% last quarter, Nebius was 454%. Nebius makes deals with Microsoft, Meta, ...
While Yandex could go bankrupt very soon ( 2-3/5 dc's closed, apps not working, robots not working, payments not working, maps show everyting in rivers and oceans, ...).
Nebius is currently going after their best growth driver. Can't blame them.
Comparing GDP, the market cap and other financials make way more sense than judging companies by how many separate projects and directions they have their spoon in.
Sometimes it's better to diversify, sometimes it's better to concentrate. There is no better decision to concentrate than to do it during the AI hype.