I have used beancount and it is significantly better than an Excel or Google Sheet. For me, the main benefit is tax lot matching and an auditable trail of sale

I have used beancount and it is significantly better than an Excel or Google Sheet. For me, the main benefit is tax lot matching and an auditable trail of sales should the IRS come knocking. It's impossible to do this properly in a spreadsheet (I mean... it is possible, but no one will complain if it's done wrong until it's too late). With beancount, matching is much more straightforward. I have a python script that does it automatically for each sale using normal FIFO, tax loss minimization, etc. Due to beancount's internal checks, I am certain that these are correct once they're entered into the ledger. There is no chance of failure, and if the IRS ever asks me to justify a capital gain / loss figure, it's very easy to point out that I keep track of all my shares and have for the past several years and I maintain a solid record of the entire history of each lot.