If in the US, plan on giving half of the profit to the government. So to keep that $15 mil, you will need to make 30 mil. Unless of course you just spend your coins or attempt to avoid taxes.
Let's see. Keep it for a year. Quit my job. Make less than $70,000 (joint) in a year. Pay that 0% tax rate. Whew, those taxes are brutal...
Here is the bracket for 2013:
January 1, 2013 -
Hold 1 Year or More
10% tax rate = 0% capital gains tax rate
15% tax rate = 0% capital gains tax rate
25% tax rate = 15% capital gains tax rate
28% tax rate = 15% capital gains tax rate
33% tax rate = 15% capital gains tax rate
35% tax rate = 18.8% capital gains tax rate
39.6% tax rate = 23.8% capital gains tax rate
Note: Obama is trying to change this for 2014 but they didn't get it done in time for 2013, so keep that in mind.
Here are the current Adjusted Gross Incomes for these brackets:
2013 Tax Brackets (For taxes due April 15, 2014)
Tax rate Single filers Married filing jointly or qualifying widow/widower Married filing separately Head of household
10% Up to $8,925 Up to $17,850 Up to $8,925 Up to $12,750
15% $8,926 - $36,250 $17,851 - $72,500 $8,926- $36,250 $12,751 - $48,600
25% $36,251 - $87,850 $72,501 - $146,400 $36,251 - $73,200 $48,601 - $125,450
28% $87,851 - $183,250 $146,401 - $223,050 $73,201 - $111,525 $125,451 - $203,150
33% $183,251 - $398,350 $223,051 - $398,350 $111,526 - $199,175 $203,151 - $398,350
35% $398,351 - $400,000 $398,351 - $450,000 $199,176 - $225,000 $398,351 - $425,000
39.6% $400,001 or more $450,001 or more $225,001 or more $425,001 or more
Long term capital gains (held more than 1 year) do not count toward AGI. Short term (held less than 1 year) do. Also, get a house payment (interest) and some kids to offset your AGI. Also, donate to your favorite charity instead of the goverment if you like them better to get into a lower bracket.