I got three e-mails with this same question yesterday! Mostly, people want to either participate in balance transfer arbitrage or grab a few new rewards cards.

To start off, we must realize that all credit scores are based on secret formulas, supposedly generated by supercomputers and mountains of data to accurately predict our creditworthiness. This results in companies like FICO never truly revealing the ingredients to the secret sauce, otherwise we could just do it ourselves and they’d have nothing to sell.

In other words, nobody truly knows the answer. Now, I have never read anything official that specifically listed “number of credit cards” as a negative factor in scoring. We can only examine what ...