If you own index ETFs then you can loan out those shares. QQQ is on that list and it's a NASDAQ index ETF. If you primarily own indexes though then you don't really own shares in the individual companies comprising that index, so I don't think you have something to loan technically. Like you might sort of own a lot of Apple through an S&P index, but you can't really deliver shares of Apple to a short seller.
Two columns to note in the link above:
* if you look at the "% Float" column in the link above, you can see that TSLA is at 32.0%, meaning that 32% of all TSLA stock is held by people that are shorting it. this calculation is a little more nuanced than this because shorts are only borrowing it and the stock kind of has two owners, but it paints the general picture: 1/3 of Tesla stock holders are there because they hope Tesla stock decreases in value. I think they're dead wrong but that's how markets are made.
* the "days to cover" column means that if all the short sellers tried to close their position (ie, buy stock in the company), how many days would it take that to happen at an average day's volume? this can be an indicator of companies ripe for a short squeeze, where a company announces unexpected good news and shorts rapidly try to close their position but not enough people want to sell and so the stock price skyrockets. This famously happened to Volkswagen: https://www.quora.com/What-are-some-of-the-greatest-short-sq...
be aware of a few things in general:
* these rates are completely out of your hands. GOGO of Gogo inflight Wifi is listed at 43% float and 21 days to cover, but its borrow rates are around 8%. I don't know why.
* in many cases, there is a short argument worth listening to and there's a reason many people are shorting a stock. GoPro/GPRO is currently paying 86% for people to lend out their shares to short sellers. You could buy GoPro and lend out your shares but then you run the risk of owning GoPro and it's a big question mark how big that risk is. I face that same risk in owning Tesla, but I think the short argument is garbage and I really believe in the company and that's enough for me.
* the tesla situation was kind of a perfect storm because it has a lot of fervent believers on both sides. companies that people are really passionate about might be hard to come by.
For whatever reason this never materialized but I don't know why. There's a possibility it may have been against SEC rules or that institutions gradually recalled their shares so as not to disturb things too much.