Wilshire Indices Which Financial Index Tracks The Thrift Savings Plan S Fund?

Which Financial Index tracks the Thrift Savings Plan S Fund? - wilshire indices

The summary of TSP S Fund have shown that monitoring of the Dow Jones Wilshire 4500 Completion Index. However, it appears that several Dow Jones Wilshire 4500 index (eg ^ DWCPT, DWCPFT ^ ^ DWCPF, & ^ DWCPs). See http://finance.yahoo.com/lookup?s=wilshire
This book really the S-fund?