You can check it on sec.gov. Yandex spend nothing on consultancy for 2014 and 2015 years

I can't be bothered to dig right now, but you're saying that a company with 5000+ employees did not use any consultants at all, zero, for 2014 and 2015? I really can't believe that.

Edit: there are many ways to hide bribes, of course. Typically it involves overpaying for something. It would be hard for even a non-corrupt tax authority to tell the difference between having bad negotiation skills and bribes.

My point is "big non-government companies in Russia doesn't pay any bribes". But you're right, it's definitely possible do hide some amount of bribe money if you really want to.