I am working on two datasets, where the first one has multiple firms' daily stock returns and the second one has monthly balance sheet items of those firms. I want to merge the dataset in such a way where the monthly balance-sheet data will join the daily return data on month basis. So in the final daily dataset a particular stock's balance-sheet item will remain fixed over month but it would be completely filled.
df1 will be merged with df2 and the final one would look like df3