Good questions! Curious how other EAs do this too

I donate 20% post tax. I also set a spending limit for myself ot 2k USD per month. Besides that I save everything.

With that savings I max out my retirement account savings each year (5500 USD in the US). That all goes into an index fund Rest of my savings mostly goes into index funds unless I have one off exciting investment opportunities (eg if my startup is raising a round. They were last year and I invested 10k)

The savings is basically earmarked for "giving me financial security and doing some good in the world later in life". I don't know if I will donate a large portion of it later, invest in a company I think will do good or give me a great return, finance any ventures I start myself. Maybe I would use it to pay for a house or something, but I would have to think very hard about that. My 2k per month spending cap is to prevent myself from having lifestyle creep so if I was to make a big purchase I would need to make sure I wasn't just indulging in luxury because I have money lying around.

I try to donate 10% of my post-tax income every year to effective charities, and I put 8% of my pre-tax income (4% from me + 4% match) into a 401k which is invested pretty aggressively. (My 401k provider asked me to pick a number, 1 to 5, corresponding to my risk tolerance and I picked 4.) 

In terms of net assets, I have about 25% in a retirement account and the rest in an investment account.

As it happens, I work for a company, Glo Foundation, that's creating a stablecoin that (we argue) works as a savings vehicle but also will generate donations for GiveDirectly -- see our post Glo Dollar, an ethical stablecoin: model, potential impact, and roadmap for more details. 

If the crypto angle is a turnoff, you could accomplish something similar by investing in (e.g.) a T-bill ETF, which is highly liquid and which will generate interest, and then give some or all of that interest away.

Triodos (the most ethical bank I could find)

Fwiw I have never been terribly impressed by Triodos' ethos. The last time I looked at the sort of projects they fund, they were e.g. investing in alternative medicine and divesting from nuclear energy, the former of which seems surreal to call 'ethical' and the latter of which is a disastrous strategy for the environment.

I would much rather invest in something with a higher interest rate and donate 50% of the difference (or whatever seems appropriate).

I like Jacob’s advice over at Put a Num on It from a few years ago. robo-investing, diversified internationally. Not keeping much beyond what you need for bills in cash. https://putanumonit.com/2017/02/10/get-rich-slowly/

I invest almost everything and don't keep much in bank accounts, but anyone who does should at least make sure they're banking at competitive rates:
https://forum.effectivealtruism.org/posts/SEXGJfj7RMRomf9ts/save-to-give-switch-banks
 

I was wondering about the same and was quite surprised why there is no EA investment option available or at least an official step-by-step guidance on non-EA investment.

We are planning to buy a house in the not too distant future and have ~100.000€ savings.

It’s currently in an investment option offered by the local government for local citizens which pay ~1% above inflation (guaranteed). But I heard that even ~3% is realistic. I’d be happy to earn that 3% and donate the difference as well.

I’m thinking of looking into the topic myself but it would be way better if someone who’s already familiar gave some practical guidance.