YOu should look at how relatively google is doing vs. other tech companies or S&P vs. individually
I'm not sure where the parent is getting 15%; Google seems to be up ~23% YTD. Today's close was an all-time high, though that might get somewhat undone in the morning.
To your point, that seems to be a bit worse than tech (~26% YTD) but better than the S&P (17% YTD).
You need to also include the 7% after market drop which Google shares saw after declaring the results.
That's not difficult considering what happened in December.