Day 20 - Vendor with highest stock value

20 - Vendor Highest Stock Value = 
VAR _StockValueByVendor = 
ADDCOLUMNS(
    SUMMARIZE(
        Suppliers,
        Suppliers[CompanyName]),
        "Stock Value",
        CALCULATE(
            SUMX(Products, Products[UnitsInStock] * Products[UnitPrice])
        )
)
VAR _TopVendor = TOPN(1, _StockValueByVendor, [Stock Value])
Return 
SELECTCOLUMNS(_TopVendor, "CompanyName", [CompanyName])