Read the following texts and table with financial data from an S&P 500 earnings report carefully.Based on the question-answer history (if provided), answer the last question. The answer may require mathematical calculation based on the data provided.

Text: subject to fluctuation and , consequently , the amount realized in the subsequent sale of an investment may differ significantly from its current reported value . fluctuations in the market price of a security may result from perceived changes in the underlying economic characteristics of the issuer , the relative price of alternative investments and general market conditions . the table below summarizes equity investments that are subject to equity price fluctuations at december 31 , 2012 . equity investments are included in other assets in our consolidated balance sheets . ( in millions ) carrying unrealized net of tax . <table class='wikitable'><tr><td>1</td><td>( in millions )</td><td>costbasis</td><td>fairvalue</td><td>carryingvalue</td><td>unrealizedgainnet of tax</td></tr><tr><td>2</td><td>bm&fbovespa s.a .</td><td>$ 262.9</td><td>$ 690.6</td><td>$ 690.6</td><td>$ 271.4</td></tr><tr><td>3</td><td>bolsa mexicana de valores s.a.b . de c.v .</td><td>17.3</td><td>29.3</td><td>29.3</td><td>7.6</td></tr><tr><td>4</td><td>imarex asa</td><td>2014</td><td>1.8</td><td>1.8</td><td>1.1</td></tr></table> we do not currently hedge against equity price risk . equity investments are assessed for other-than- temporary impairment on a quarterly basis. .
Question: in 2012, what was the total combined amount of the fair value and the cost basis for the the bm&fbovespa s.a .?
Answer: 953.5
Question: and what was the difference between that fair value and the cost basis for the bolsa mexicana de valores s.a.b . de c.v .?

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