Malkiel

Dollar Cost Averaging This Recession

It would be tax form madness to do it this way for anything other than some kind of tax-deferred retirement account.

For a taxable account, consider a simpler strategy; let a chunk of cash build up in the account and use your broker's trading software to set up a buy triggered by reaching your preferred low price-point. You may not reach that price point, but if you get close enough to suit you you can step in and execute the buy manually. Buying a chunk at a reasonable discount once a year beats dealing with tax complexity for multiple share purchases (actually, the later selling is the problem).