If you don’t have an emergency fund, I would put some or all of it into something like a money market account. It won’t grow very much, but it’s safe and is quick and easy to withdraw when needed.
Otherwise depends on your age and situation, but an index fund (S&P 500) is almost always the right choice. It’s flexible, doesn’t usually lock you in, and will generally do very well in the mid-to-long term. If we hit a recession you might get stuck holding the shares for several months to a few years. The last thing you want to do is panic sell in that situation.
If you have any debt, paying that down is a very smart move, especially if the debt is charging more interest than your investment can earn. Future you will thank you.
I have my emergency fund, and no debt. If I were to lose this $10K, it wouldn’t impact my life. I’m comfortable with taking $10K out of my bank account and doing something with it but I don’t know how to go about that. I don’t know how to open an index fund or money market account.
I’m going to second (third, fourth, fifth) the Roth IRA recommendation. You can set it up with Schwab or whoever and can make recurring contributions too (set it and forget it) there are income limits so if you are really raking it in one year you can’t contribute that year but whatever you put in there is still (usually) going to grow in value. If you have an emergency situation and need the money you can withdraw contributions, not earnings, ahead of retirement, so it’s not lost to you, but working for you and much easier at tax time, no worries about how to report it.
Pay down your debts first.
Buy 10 Babies in Arkansas.
With zero information on your situation, it’s difficult to say. If you have debt, paying that down/off is generally priority one. If you are debt-free, then you have options. Your age, stability, goals, and other factors would generally dictate what type of action to take. Were it me (early 40s, very low interest rate home loan), I’d put it into an index fund where I’ve already got some investments. In my case, I’m investing for retirement in about 25-30 years (as if I’ll be able to do that, but one can hope).
Bees.
