The Williams Commercial Index is available on TradingView:

https://in.tradingview.com/script/KKBYQPCZ-William-s-Commercial-Index/

It is also discussed in this ProRealTime forum topic:

https://www.prorealcode.com/topic/commoditer-of-trader-cot/#post-90159

study("William's Commercial Index", shorttitle="WILLCO", precision=2)
force_root = input("", title="Override Product")
is_includeoptions = input(false, type=bool, title="Include Options")


fxroot =
	  ticker == "USDCAD" ? "CD" : 
	  ticker == "USDCHF" ? "SF" : 
	  ticker == "USDCZK" ? "CZ" : 
	  ticker == "USDHUF" ? "FR" : 
	  ticker == "USDILS" ? "IS" : 
	  ticker == "USDJPY" ? "JY" : 
	  ticker == "USDMXN" ? "MP" : 
	  ticker == "USDNOK" ? "UN" : 
	  ticker == "USDPLN" ? "PZ" : 
	  ticker == "USDRUB" ? "RU" : 
	  ticker == "USDSEK" ? "SE" : 
	  ticker == "USDZAR" ? "RA" : 
	  ticker == "EURUSD" ? "EC" : 
	  ticker == "AUDUSD" ? "AD" : 
	  ticker == "GBPUSD" ? "BP" : 
	  ticker == "NZDUSD" ? "NE" : 
	  ticker == "BRLUSD" ? "BR" : 
	  ""
root = force_root == "" ? fxroot == "" ? syminfo.root : fxroot : force_root
code = root + (is_includeoptions ? "_FO_L_ALL" : "_F_L_ALL")


is_inversed = 
	  ticker == "USDCAD" ? true : 
	  ticker == "USDCHF" ? true : 
	  ticker == "USDCZK" ? true : 
	  ticker == "USDHUF" ? true : 
	  ticker == "USDILS" ? true : 
	  ticker == "USDJPY" ? true : 
	  ticker == "USDMXN" ? true : 
	  ticker == "USDNOK" ? true : 
	  ticker == "USDPLN" ? true : 
	  ticker == "USDRUB" ? true : 
	  ticker == "USDSEK" ? true : 
	  ticker == "USDZAR" ? true : 
	  false


long_total = security("QUANDL:CFTC/"+code+"|4", "D", close)
short_total = close
oi = security("QUANDL:CFTC/"+code+"|0", "D", close)


long = is_inversed ? short_total : long_total
short = is_inversed ? long_total : short_total
net = long-short
willco = net / oi


length = input(24, title="Period (weeks)")


max = highest(willco, length)
min = lowest(willco, length)
index = 100 * (willco - min) / (max - min)


index_adopted = security("QUANDL:CFTC/"+code+"|5", "D", index)


plot(index_adopted, color = black, title="Index", style=line)
hline(80, color=blue, linestyle=dashed)
hline(20, color=blue, linestyle=dashed)