More than 1.5million people have at least £100,000 saved in their Isa. However, if you leave it in cash, it's likely to underperform stocks and shares and may even lose value over time due to inflation.Instead, you could invest your £100,000 in a balanced portfolio of shares, bonds and other assets, so it grows over time and you hopefully end up with more than you would have made.The right portfolio depends on how much risk you want to take and when you need the money.Andrew Prosser, of InvestEngine, suggests a 'core and satellite' approach, where the heart of your fund is a global tracker fund if you're going for growth, or a global bond fund if you're investing to earn a regular income.A global tracker is a low-cost fund that follows thousands of companies worldwide.For most people, the core should be a balance of the two. Around this core fund you can add 'satellite' funds or shares that give you exposure to commodities such as gold; investment themes that could outperform the world markets, such as healthcare or technology, or different geographical areas you think are exciting.For most of us, the global fund will dictate the bulk of performance, so take your time and do research to get this right.Dan Coatsworth, head of markets at AJ Bell, says: 'Tracker funds can be ideal stepping stones.' He suggests beginners put some of their portfolio into global equity funds, as you aren't 'making a call on a specific industry or part of the world'. More than 1.5million savers have at least £100,000 in their Isa, but if you leave it in cash it's likely to underperform stocks and shares and may even lose value over time due to inflation AJ Bell's Dan Coatsworth, suggests beginner investors should put some of their portfolio into global equity funds, as you aren't 'making a call on a specific industry or part of the world' If the SpaceX listing intrigues you then you can invest in WisdomTree Space Economy, an exchange-traded fund that gives you exposure to satellite businessesTrackers also tend to have low charges. These funds all track one of four global indices of shares, meaning their performance is similar, so you may as well pick the one with lowest charges, currently the Invesco MSCI World fund.If you put your £100,000 into this fund, though, expect a bumpy ride, as all your investments would be in shares rather than spread across different assets. You would be missing the ballast that makes your investment less volatile.Most have a proportion of their investments in corporate and government debt, as well as alternative assets like gold and property.When times are rough, these other assets come into their own. Gold often rises when everything else falls, while bonds are steadier than equities.Broadly, the more bonds you have in a portfolio, the steadier its return will be, but the slower it might grow. More risk-averse investors have more of their money in bonds, and more risk tolerant investors have more in shares.For medium risk investors, a structure similar to the Wealthify Confident Plan portfolio, with around 45 per cent in shares, 40 per cent in government bonds, 4 per cent in corporate bonds and the rest in alternatives might work, while the more wary might prefer a portfolio similar to its Cautious Plan, with 10 per cent in shares and 82 per cent in bonds.You can use multi-asset funds such as the Vanguard LifeStrategy to create a portfolio that matches your risk appetite and timeframe. Those with a long-term lens could choose the 80 per cent equities/20 per cent bonds version, while those using the £100,000 to fund retirement could have 40 per cent in equities and 60 per cent in bonds.Alternatively, you could pair the Invesco Equity Fund with the Vanguard Corporate Bond Fund, or HSBC's Global Government Bond ETF, which Mr Coatsworth says are two top-bond trackers among AJ Bell clients.Once you've got the core equity and bonds funds right, your satellite funds are where you can use some of your remaining lump sum to invest in companies, sectors and geographies that interest you.Those excited by renewable energy could pick up a specialist investment trust in this area at a discount. The Renewables Infrastructure Group trades at a 29 per cent discount to the value of its assets, for example.If the SpaceX listing intrigues you, then you can invest in WisdomTree Space Economy, an exchange-traded fund that gives you exposure to satellite businesses and rocket launchers.If you have received £100,000 in a windfall, say from an inheritance, you will want to shelter it from taxes as quickly as you can.Put as much you can into a tax wrapper to save on capital gains and dividend tax as your lump sum grows. You can place £20,000 a year into an Isa and £60,000 into a pension so they can grow tax-free, but a pension won't be right if you need the cash before age 55 (rising to 57 in 2028).