Shares of Alphabet opened nearly 3 percent higher Tuesday, pushing the technology giant's market capitalization past Apple to become the world's most valuable public company.
Alphabet has a market cap of $547.1 billion, higher than Apple's $529.3 billion as of 9:45 a.m. ET.
Apple's massive market cap is still trailed by Microsoft ($425.7 billion), Facebook ($326.2 billion) and Exxon Mobil ($310.1 billion) to round out the list of the world's five biggest companies.
Alphabet was already set to take the title Monday night, before sealing the deal Tuesday morning. At Monday's after-hours levels (which technically reflect an indication, but not the real-world value), Alphabet's market cap hit roughly $570 billion, eclipsing Apple's market cap of about $535 billion. Shares of Apple opened Tuesday down nearly 1 percent.

