When Sergio arribed to McLaren, did so only with Claro support. Claro payed for his salary and no more. So Sergio went to Woking only on his own talent.
Now, Telmex is supporting him an this mean about 15 millions dollars in sponsorship, which is not that big now a days in F1.
A think that FI gets more resorces than they could get signing Sergio by his own becouse of McLaren’s support to Checo’s deal with them, I mean, McLaren transference of technology and technical support worts more than telmex sponsorship itself, at the end they got a great and young driver and a twiece the support they could get.