Google-parent Alphabet reported quarterly earnings that missed analysts' estimates on Thursday, as it earned less per click on its properties. The company's costs also ticked higher, as it invested in talent and the core business. Revenue topped expectations, led by YouTube and mobile search, chief financial officer Ruth Porat said in a statement. But a Google representative told CNBC that YouTube has been slower to pick up the slack from Google's other advertising properties. Sundar Pichai delivers his keynote address during the Google I/O developers conference in San Francisco on May 28, 2015. ROBERT GALBRAITH / Reuters file Related: Alphabet's Nest Security Camera Just Got Way Smarter The company posted fourth-quarter earnings per share of $9.36, adjusted and excluding items, on revenues of $26.06 billion.