I see where you are coming from, but if you step back for a second, this just sounds bizarre.
OP now has more money than they need or ever have had, and instead of relaxing and finally caring about something other than money, you suggest they actually start caring more about money.
You would definitely suggest reading up on how to successfully keep ponies, right?
It's a smart thing to do learn money-management at any point of your life, even more with a sudden windfall like this. The OP seems like a straightforward guy who isnt really interested in money hence this post.
So it's up to him what kind of impact he'd like to have to the world around him. If you really get down to it there's no wrong or right way to proceed. To maintain that wealth he should definitely learn how to manage it. To spend that money on things he deems important he probably doesnt need to learn much money-management.
Wisest thing in my mind, and what others have suggested, is to wait and ponder what he really wants to do in life. Maybe read some money-management books, sure. To see if it's any interest to him.
This is a false statement. In fact, it is false ipso facto.
In this case, selling the ponies and do something they like with the money.
Or selling some ponies, and pay someone to take care of the rest and make them reproduce/sell them, so that you can live with the pony-benefits.
It might not be optimal pony-wise, but it definitely makes more sense life-wise.
This is how the rich stay rich. You can't just spend (I mean, you can if you're really disciplined and treat it like a retirement income). When you've got a lot of money you need to park your money somewhere it appreciates and then skim off some of the appreciated amount when you want to use it.
The only way you'd spend all this money is if you started doing crazy things like buying speed boats and other such nonsense.
To wit, this is probably the wrong forum if people are going to respond as you did, Sir, so he is probably better off over on Bogleheads.
Though my personal game plan was take one of they founders of nominet worth well over 100m at one point) out for lunch in the best restaurant in Brighton and ask hime what he would have done differently :-)
Or do a cheeky letter to one of the Rosthchild's I met at fast Tuesday years ago
Plus, you need to factor in their future earnings. When people speak of retirement, they really mean just doing something else they're interested in. The likelihood of these activities generating income, at some stage, is substantial.
Also why would anyone need to spend 300k in a year? If you own your house, there's not much to spend other than utilities, food and a couple of holidays... Or am I missing something?
the reason i bring up college expenses (which are about $70k/year at top US schools) is that parents tend to do whatever they can to give their kids the best possible chance in life. even if someone is not purchasing luxuries for themselves, it's not hard to spend tons of money on children. about $600k needs to be set aside if he wants to guarantee that his children can attend any college they can get accepted to. in the meantime, there are plenty of expensive things he can do to improve their chances of admission. maybe this means buying a house in a better school district or paying for private school (possibly >$40k per year per child). maybe it's private SAT prep to boost test score. extracurriculars are also very important for admissions (and are enriching in their own right), and the most impressive ones aren't cheap either. there's always something you can spend more money on to improve life outcomes for your kids.
you can't just say "I have a lot of money, I'm going to spend modestly, and everything will be alright," and have it be so.
There can also be an urge to buy that vacation home in Tahoe or Jackson that you always dreamed of. Maybe you used to rent a house in Tahoe for a weekend every winter before windfall. Now you buy a place and have a mortgage for a cabin that you use a handful of times a year.
Before you know it, you can have a lot more expenses creep up.
It doesn't take a lot of reading to get towards get a nice umbrella policy, talk to an estate lawyer, and then put most of the money in a diversified bond fund and a diversified stock fund', and plan to pull out a small % per year as your annual budget; allow for large expenses occasionally, but be aware of the impact on your future annual budget. Maybe set aside a specific amount money (in consultation with your significant other) for unwise investments, if you want to learn first hand why they're not recommended.