When selling all shares of a security, why does cost basis remain -$.01?

Question

Manually entered a security sale, clicked radio box to sell all shares. The Security Detail View shows zero shares held with a cost basis of -$.01.

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UKR · Accepted Answer

Somewhere there's a rounding error.
A transaction was entered in such way that Quicken calculated the total cost as
number of shares * price per share +/- commission 
resulting in fractional cents being rounded up or down. This may also show up as a discrepancy between total cost in Quicken when compared to brokerage statement.
It's been my experience that it's better to enter
number of shares, commission and total cost
allowing Quicken to calculate price per share to as many decimal places as it needs to. That avoids penny differences between Quicken and brokerage statement.