"Buffett’s derivative bets on stock market gains boosted earnings by $390 million in the second quarter, compared with a loss of $1.17 billion a year earlier. Fluctuations in the value of the contracts are recorded in net income each quarter, even though the wagers won’t be settled until 2018 or later."
"One nugget from the reports we're always interested in is the value of his long-term derivative bets on the global stock markets. In case you forgot, Berkshire had sold put options on the S&P 500, FTSE 100, Euro Stoxx 50, and the Nikkei 225.
Berkshire collected premiums when it sold these options. Because they are put options, Berkshire is obligated to pay the option buyer should the indices fall below the exercise price. It's important to note that these are European style options, which means they can only be exercised at maturity. As a general rule, the value of these positions increase when stocks go up and vice versa.
In Q3, their value fell by $534 million. Of course, these are just paper losses as Buffett expects to hold them until they expire."