When you think about retirement planning, it tends to be long-term investments that come to mind. Whether that means funding a 401(k), setting up a private retirement fund, or even investing in a property you can sell down the road to boost your finances, the idea is similar: investing now for significant returns later. This is the fundamental point of retirement planning, and something everyone should engage in one way or another.

But setting up long-term savings doesn’t necessarily mean that you can’t engage in other ways of making money during retirement. Our tips for making up for a late start on retirement savings touched on this idea by suggesting work in the gig economy. This is basically a new term for side jobs and small ventures that people do in their spare time to generate extra income — something plenty of retirees engage in as much out of interest for a particular project as a need for cash. But just as you might consider getting into a few gigs here and there to boost your retirement fund, you can also take on a different form of investment altogether, and engage in more active asset trading.

The difference between trading and investing is generally understood to be about time. Trading is done regularly and can be treated like a job, in which any given day or week may yield a financial return; investment is more about holding a position over time for a larger (and more likely) return later on. Your 401(k) is essentially an investment. But to supplement a plan like this, as well as give yourself another “gig” to focus on well into your retirement if you take to it, there are various trading markets you might consider exploring.

1. Stock Trading

Day trading in the stock market is a very common practice, and one you can even come to enjoy if you happen to have a mind for it. It can generate profits for you on a regular basis, and it can give you something to do that keeps your mind active and even keeps you tapped into the political and industry news of the day.

Buying and selling stocks to take advantage of shifting share prices is an age-old practice, but it does take some getting used to, and it’s important not to try it without a sound understanding of how the market works, and what strategies are known to pay off. That said, stock markets have become more accessible thanks to a selection of modern trading apps. These apps make it so simple to conduct trades, in fact, that there are some concerns that they make trading too easy — in that they can lead some to take a careless or reckless approach. So long as you stick to a sound strategy though, an intuitive low-fee investment app can make stock market day trading a perfectly reasonable option.

2. ETF Trading

If you’re interested in market trading but you don’t have experience with building up your own stock portfolio, the ETF market may be a suitable alternative for you. ETFs are all different, but the fundamental concept is that they bundle different assets together in order to provide traders with strategically diversified mock portfolios. Functionally, trading ETFs works much like buying and selling stocks. But you’ll have fewer things to keep track of and less of a challenge setting up your own portfolio.

3. Forex Trading

The forex market, also known as the currency exchange, can look fairly complicated at a glance. Currency values are listed sometimes to four decimal points, trading volume is higher than in any other market, and people are participating from all over the world. All of this can give the impression that this is something of an experts-only environment that the average person seeking a supplemental investment venture might not understand.

The truth, however, is that trading forex pairs is very simple. The traditional way to do it is to buy and sell pairs (representing one currency’s value relative to another) almost as if they were stocks, and hope to earn money off of changes in value. But you can also trade in the forex market via CFDs or futures — both of which enable you to speculate on currency values without having to buy and sell them. These are all pretty convenient options, which coupled with the flexible hours in the forex market can actually make it an appealing one to get into.

4. Cryptocurrency Trading

Not unlike forex, cryptocurrency can seem somewhat intimidating at first glance. To be sure, understanding cryptocurrency can be a process that amounts to ongoing education on the matter. But there is now enough material — in the form of books and podcasts, day-to-day news, and web content — that newcomers can learn everything they need to know in order to trade in this market.

Actually, once you understand cryptocurrency, the process of buying and selling assets is fairly straightforward. It’s difficult, mind you, because cryptocurrencies tend to be volatile and even skilled investors are still working out how to read the market. But moving forward, crypto trading is likely to only become more popular, such that it could make for another mainstream trading option.

None of these trading methods should replace your retirement investments. But if you’re curious about ways to supplement those investors, or you’re interested in a financial venture you can stay active with after you retire, they’re all worth a look.