(Bloomberg) -- Alphabet Inc. shares are on track for their biggest quarterly gain in 20 years, the latest reflection of how investors are turning more positive on the Google parent as it strengthens its foothold in artificial intelligence. The stock is up about 38% this quarter, its biggest such gain since mid-2005. The move brings Alphabet’s year-to-date gain to nearly 30%, compared with a 17% rise for the Nasdaq 100 Index. The stock was 1.4% lower on Tuesday. Recent gains followed a long-awaited antitr ...