The term Wilshire 4500 Completion Index refers to a composite that includes companies appearing in the Wilshire 5000 Total Market Index, less the companies appearing in the S&P 500. The Wilshire 4500 Completion is published and maintained by Wilshire Associates.
The Wilshire 5000 Total Market Index is designed to measure the performance of the large, mid, small, and micro capitalization companies in the United States equities market. The index is a composite of all the securities (primary equity, common stock, REIT, or Limited Partnership) that have a primary market listing in the United States. The Wilshire 4500 Completion Index includes the securities appearing in the Wilshire 5000, excluding those securities found in the S&P 500.
First published on December 31, 1983, the index contains U.S. headquartered equities with readily available prices. Securities found in the Wilshire 4500 will trade on the AMEX, NYSE, or NASDAQ exchanges. The index is a float-adjusted, market capitalization-weighted measure. Rebalancing occurs monthly or concurrently with the rebalancing of the S&P 500. The performance of this index can be monitored via the stock ticker symbol W4500.