The investment platform will waive its £10 monthly Sipp fee until April 2021, which amounts to a further £110 saving.
When announced last month (March), the offer originally applied to all new accounts opened between March 3 and April 3 this year but the closing date has also been extended to April 30 so more savers can take advantage of the low costs at a time when markets are suffering.
Existing clients who have an Isa or a trading account but no Sipp are also able to take advantage of the offer.
Moira O’Neill, head of personal finance at Interactive Investor, said: “Our free Sipp offer for one year doesn’t just apply to transfers in from rival providers, but could equally encourage someone to set up a Sipp for the first time, including existing customers who don’t have a Sipp – with us or anyone else.
“This Sipp offer means that investors would be able to have everything under one roof – their Sipp, Isa, trading account, and as many free junior Isas as they have children – for just £9.99 per month.”
She added: “Don’t underestimate the power of cutting your fees on pensions by a few hundred pounds a year. Even small savings can compound up into life-changing sums over a period of many years.
“You can’t control the markets (with markets down) but you can control your costs – and this offer will be a big help.”
The investment platform does not charge a fee to set up or close the Sipp and clients also do not face a charge when transferring in funds.
There is also no charge on transferring to another provider but the firm charges £500 plus VAT on transfers to an overseas scheme.
There is also a £10 per month charge for drawdown.
At the beginning of this year (January 7), Interactive Investor scrapped its regular investing fee in a move which meant investors no longer had to pay a 99p charge per investment, providing they invested at least £25 per month.
The platform said it hoped the move would leave customers with "just one easy-to-understand, pounds-and-pence monthly flat fee."
In February, the company announced it was set to buy rival platform The Share Centre for £61.9m, with the consumer platform market beginning to mirror the wave of consolidation currently gripping the adviser platform landscape.
What do you think about the issues raised by this story? Email us on email@example.com to let us know.