Disclaimer: IANAL or a financial expert. This information is relevant in the US, but Swedish brokerages may do something similar.
In the US, brokers cannot lend out your shares without your knowledge. Brokerage customers can opt into a program called Fully Paid [Securities] Lending, in which the broker pays you a monthly fee to lend your shares out to short sellers. The fee you're paid is higher for securities that are harder to come by; shares of an up and coming marijuana company will be much more rare than large-cap stocks in the S&P 500. (Brokerages often own their own shares of popular stocks that they can lend out, so there's no need to pay customers for access to them.) You can recall the shares at any time, so they're still considered liquid. The only "catch" is that you can't vote as a shareholder without first recalling them.
Here are some product pages for FPL programs run by Schwab[1] and Fidelity[2]. Most (all?) large US-based brokerages seem to offer this in some form.
I believe you need to upgrade to the premium Robinhood Gold before they can lend shares. It isn't the default, AFAIK. But a lot of people who post online about trading (selection bias) use Robinhood Gold.
Here is an idea of how much you'll need invested into a rarer stock or your typical retail brokerage account:
Fidelity: "*You must have at least $250,000 in your Fidelity brokerage account(s) to apply."
Schwab depends on the stock, but it seems many people get an email when they have over $100k of an eligible, especially rarer, security.
TDAmeritrade does not offer it, but they were bought out by Schwab so that will likely change as your account is transferred over.
"Interactive Brokers earns 15% annualized income from lending shares with a value of $10,000 and it posts $10,000 cash collateral to a participant's account"
In the US, brokers cannot lend out your shares without your knowledge. Brokerage customers can opt into a program called Fully Paid [Securities] Lending, in which the broker pays you a monthly fee to lend your shares out to short sellers. The fee you're paid is higher for securities that are harder to come by; shares of an up and coming marijuana company will be much more rare than large-cap stocks in the S&P 500. (Brokerages often own their own shares of popular stocks that they can lend out, so there's no need to pay customers for access to them.) You can recall the shares at any time, so they're still considered liquid. The only "catch" is that you can't vote as a shareholder without first recalling them.
Here are some product pages for FPL programs run by Schwab[1] and Fidelity[2]. Most (all?) large US-based brokerages seem to offer this in some form.
[1] https://client.schwab.com/secure/file/P-5182696/MKT33373-05.... [2] https://www.fidelity.com/trading/fully-paid-lending