The stewards at the Spanish Grand Prix decided to take no further action regarding the collision between Lewis Hamilton and Nico Rosberg.
Rosberg took the lead with a good move around the outside of Turn 1 on the opening lap, but was in the wrong power unit mode which allowed Hamilton to close quickly on the approach to Turn 4. Rosberg moved to the inside to defend and Hamilton swerved to the right which left him on the grass.
With Hamilton unable to slow the car for Turn 4 as a result, he slid sideways into his team-mate, wiping both cars out. The stewards decided to investigate the incident after the race and having heard from both drivers decided to take no further action, "determining that Car 6 [Rosberg] had the right to make the manoeuvre that he did and that Car 44's [Hamilton] attempt to overtake was reasonable".
The stewards explanation in full reads:
"The incident concerned started when Car 6 dropped into an incorrect power mode, as set by the driver prior to the start. This created a significant power differential between Car 6 and Car 44 at the exit of Turn 3 coming onto the straight, resulting as much as a 17kph speed difference between the two cars on the straight. Car 6 moved to the right to defend his position, as is his right under Article 27.7 of the Sporting Regulations. Simultaneously Car 44 as the significantly faster car with, at that time, apparent space on the inside, moved to make the pass. Article 27.7 requires the leading driver to leave room, if there is a "significant portion" of the car attempting to pass alongside. Car 44 had a portion of his front wing inside Car 6 small fractions of a second prior to Car 44 having to leave the right side of the track to avoid an initial collision, which may have led him to believe he had the right to space on the right. Once on the grass on the side of the track Car 44 was no longer in control of the situation.
"Having heard extensively from both drivers and from the team, the Stewards determined that Car 6 had the right to make the manoeuvre that he did and that Car 44's attempt to overtake was reasonable, and that the convergence of events led neither driver to be wholly or predominantly at fault, and therefore take no further action."