Ehhh you get into meta when it comes to options and futures, but I would argue they still aren't zero sum. I mean, you could argue almost everything money wise can be looked at as zero sum.
If a VC buys a 10% stake in company ABC for $1 million the trade looks like:
VC: -$1,000,000, +10% equity (worth $1,000,000)
Net = $0
ABC: +$1,000,000, -10% equity (worth $1,000,000)
Net = $0
Now let's say ABC doubles their valuation. Now the trade looks like:
VC: -$1,000,000, +10% equity (worth $2,000,000)
Net = +$1,000,000
ABC: +$1,000,000, -10% equity (worth $2,000,000)
Net = -$1,000,000
Obviously the $1,000,000 helped ABC double their valuation, which means that the transaction was not zero sum. Same could be said about all investments and to a lesser extent, options and futures. You can't ignore the context of the trades such as using put options to hedge a long position, for example.
