Currently [as of February 24, 2024] the five biggest companies are, in this order, Microsoft, Apple, Aramco, NVIDIA, and Amazon.

Valuations will be taken from companiesmarketcap.com, unless it becomes unavailable or blatantly unreliable, in which case an alternate source will be found.

This question was used for OPTIC's spring 2024 in-person forecasting tournament for undergrads in London. If that sounds like fun, register for the next one or chat with the organizers!