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New Interactive Investor* customers can get between £100 and £3,000 cashback when opening a self-invested personal pension (Sipp) by 31 August.

In previous months the platform was offering a flat £200 cashback when investing at least £20,000.

That deal was better for those with a smaller pot to invest or transfer. The new promotion means that those with a pension of between £20,000 and £49,999.99 qualify for just £100 cashback.

But if you have a pot of £100,000 or more, the new promotion could net you more. 

The payout steps up from £250 on that amount to as much as £3,000 – but to qualify for that level you'd need a huge £1.5million.

Summer cashback deals are few and far between, with the best offers usually launching in the months leading up to tax year end on 5 April.

When transferring a pension, make sure that you don't lose any valuable benefits such as a protected pension age. 

You also shouldn't choose an investment platform based on an offer alone – compare it against others and pick one that suits your needs and goals.

> Find out more at Interactive Investor* 

Interactive Investor is paying cashback in tiers, increasing to £3,000 for pots of £1.5million or more:

Keep in mind that the promotion is only open to new customers who open a Sipp as their first Interactive Investor account between 1 August and 31 August.

Both new deposits and transfers from other providers count towards the value of your pot. 

You need to start any transfers within the offer period, and these must then be completed within six months.

You must also open a trading account by the end of February, although you won't necessarily need to use it – Interactive Investor will pay your cashback into this.

We like that Interactive Investor pays the cashback quickly. You should receive it within 30 days of meeting the qualifying criteria, if you open a trading account during that time.

If you leave opening the trading account until later, you won't get the cashback until 30 days after you've done so.

You do need to keep your Sipp open and funded for at least 12 months, otherwise the platform may reclaim the cashback. 

Cashback gives your portfolio a welcome boost if you're already looking to open a new Sipp or transfer an existing pension to a new platform. 

But as mentioned, make sure you don't lose any valuable benefits when transferring. 

You can find out how the platform performs in our Interactive Investor review.

Interactive Investor* is a 'full-fat' investment platform whose main rivals include AJ Bell, Fidelity and Hargreaves Lansdown.

Unlike newer app-based platforms like Freetrade* and Trading 212*, these platforms charge account and trading fees. 

But in return, investors can usually access more comprehensive customer service and investment research.

The right platform for you depends on the type of investor you are, how much support you need – and whether you're keen to save money on fees, or are happy to pay them for extra bells and whistles.

Interactive Investor charges a flat account fee of £5.99 a month for portfolios of up to £100,000 and £14.99 a month above that. 

This gives you access to all its accounts – a trading account, stocks and shares Isa and Sipp.

Dealing charges start at £3.99 a trade for funds, £3.99 a trade for UK and US shares and £9.99 a trade for international shares.

We like Interactive Investor's flat fees, because they can help keep your costs down as your pot grows.

It won't be the cheapest for smaller pots. But when investment platforms charge account fees as a percentage of your investments, these can balloon as your funds get bigger.

If you trade regularly however, the dealing fees will really add up – and you might prefer a platform that doesn't hit you with these charges.

Our pick for a platform that gives you access to a similarly wide range of investments as a full-fat platform – including funds – while charging no account or dealing fees is Freetrade*.

You can check the fees and decide on the right platform for your pension by reading our guide to the best Sipps.