Assuming you keep $10K in Ally for 5 years at 2.99% APY you would have $11,589.26.
Going with a 40% tax rate that means you earned $953.56 post-tax dollars.
Alternatively with Bank Direct you would earn 60,000 miles and $25, or $15 post tax.
So in that scenario it's 1 mile or (938.56/60,000) = 1.564 cents.
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For 2 years, $10K at 2.74% APY you would have $10,555.67.
Going with a 40% tax rate that means you earned $333.40 post-tax dollars.
Alternatively with Bank Direct you would earn 24,000 miles and $10, or $6 post tax.
So in that scenario it's 1 mile or (327.40/24,000) = 1.364 cents.
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In short, before I was sure I would dump a nice chunk of money in Ally, now I'm not really sure...