yahoo data download error with power query

deniztopcu 

That URL doesn't return JSON data, so you should use Web.Page(Web.Contents(...)) instead.

let
    tblSymbols = Excel.CurrentWorkbook(){[Name="tblSymbols"]}[Content],
    #"Değiştirilen Değer" = Table.SelectRows(tblSymbols , each ([Symbol] <> null) ) //and ([Value] <> "0")
,
    #"Changed Type" = Table.TransformColumnTypes(#"Değiştirilen Değer",{{"Symbol", type text}}),
   GetBaseURL = Table.AddColumn(#"Changed Type", "BasedURL", each Excel.CurrentWorkbook(){[Name="tblParameters"]}[Content]),
    #"Genişletilen BasedURL" = Table.ExpandTableColumn(GetBaseURL, "BasedURL", {"ParamVal"}, {"ParamVal"}),
    ReplacedSymbol = Table.AddColumn(#"Genişletilen BasedURL", "ReplaceSYMBOL", each Text.Replace([ParamVal],"SYMBOL",[Symbol])),
    GetSourceValue = Table.AddColumn(ReplacedSymbol, "GetData", each Table.SelectRows( Web.Page(Web.Contents([ReplaceSYMBOL])) , each [Caption] = "Top Mutual Fund Holders")[Data]{0}),
    #"Expanded GetData" = Table.ExpandTableColumn(GetSourceValue, "GetData", {"Holder", "Shares", "Date Reported", "% Out", "Value"}, {"Holder", "Shares", "Date Reported", "% Out", "Value"})
in
    #"Expanded GetData"

Add steps to clean up the data types at the end.