Following Follow this topic Unfollow Follow this topic NI225 ...more info The Nikkei 225 is better known as the Nikkei index, or the Nikkei Stock Average. It is an index for the Tokyo Stock Exchange. Sign up to comment Tag your Squawks to reach a wider audience. Attach images or documents Attachments Close Be the first to write a squawk about NI225 by typing into the box above.