= LET(
NetPurchase, FILTER(Purchase[Net Pur], Purchase[Stock Name]=@StockName),
PurchaseDate, FILTER(Purchase[Pur Date], Purchase[Stock Name]=@StockName),
CurrentValue, SUM(FILTER(Purchase[Curr Vale], Purchase[Stock Name]=@StockName)),
TransactionCount, ROWS(NetPurchase),
k, SEQUENCE(1+TransactionCount),
values, IF(k<=TransactionCount, NetPurchase, CurrentValue),
dates, IF(k<=TransactionCount, PurchaseDate, TODAY()),
XIRR(values, dates) )
= LET(
TransactionCount, ROWS(Purchase),
k, SEQUENCE(1+TransactionCount),
values, IF(k<=TransactionCount, Purchase[Net Pur], SUM(Purchase[Curr Vale])),
dates, IF(k<=TransactionCount, Purchase[Pur Date], TODAY()),
XIRR(values, dates) )