Missing information on 1099B
I sold a mutual fund that I purchased in 1999 this past year. The 1099B from Wells Fargo did report the basis from 2012 to 2021 to the IRS but not the basis from 1999 to 2011. They did record all of the transactions with basis from 2001-2011 which I think is what I would send to the IRS along with Form 8453. But for the transactions including the original purchase in 1999-2000, the cost or other basis has N/A and the dates of the original purchase and dividends are not included, only the date sold (1c) and proceeds (1d). I kept all of my statements so I can determine my cost basis. So I think I need to record all of those transactions on form 8949 but do I need to send copies of my original purchase and monthly statements to the IRS along with form 8453? Just not sure what supporting documentation the IRS requires.