The Lifetime ISA (LISA) launched last year allowing those aged 18-39 save up to £4,000 a year where they’ll receive a government bonus of 25% (excluding investment interest or growth), £1,000 on top.

The money can be used to buy your first home or for retirement, but for first-time buyers, the sum can be used to buy a property worth up to £450,000 nationwide. LISA contributions can continue until the age 50.

Given the LISA is similar to the Help to Buy ISA (H2B ISA) launched in December 2015, first-time buyers may hold both a H2B ISA and a LISA this tax year (though you will only be able to use the bonus from one of the schemes when purchasing a first home, both if you use the H2B ISA for property and LISA for retirement).

At the time of launch, the government said it will allow H2B ISAs to be transferred to LISAs, and special rules would apply for the 2017/18 tax year. But platforms have started to introduce earlier deadlines for the move (more on this below) – some as early as 1 March 2018. See YourMoney.com’s First-time buyer: Should I transfer my Help to Buy ISA to the Lifetime ISA? for more information.

Special Lifetime ISA rules this 2017/18 tax year

Until 5 April 2018, you can transfer your H2B ISA including interest (valued at 5 April 2017) to a LISA without the amount contributing to the £4,000 annual LISA allowance. Any funds built up on or after 6 April 2017 will count towards the LISA limit for the year.

By taking advantage of the special rules, this means you’ll be able to invest up to £4,000 in a LISA and up to £16,000 into a cash, stocks and shares or Innovative Finance ISA (remember the annual limit is £20,000).

Further, the whole amount saved will benefit from the 25% government bonus. But transferring the H2B ISA to a LISA from 6 April 2018 onwards won’t receive the same beneficial treatment.

In money terms, if you contributed the maximum into a H2B ISA from December 2015 until April 2017, you would have saved £4,400, meaning the money would be eligible for the 25% bonus (£1,100).

LISA provider AJ Bell, explains: “Because this doesn’t affect your LISA allowance, savers can contribute an additional £4,000 to their LISA and receive a 25% bonus of £1,000. This means you could pay in a total of £8,400 and government bonuses have boosted the amount to £10,500.”

Deadline dates to note

You can of course transfer your H2B ISA to a LISA in the new 2018/19 tax year, but you won’t benefit from the special LISA rules as noted above.

H2B ISA savers looking to transfer money to the only cash LISA offered by Skipton Building Society and benefit from the special LISA rules, have until 1 March to make the move.

It has set this earlier than tax-year end date for transfers as it wants to allow 30 days for the process, as given in government guidance for such moves.

And as Skipton is the only cash LISA provider, it is expecting up to 9,000 transfer requests.

If you have a H2B ISA and are thinking of transferring it to one of the handful of investment LISA platforms, here are the deadline dates you need to be aware of to benefit from the special rules:

AJ Bell: While no deadline date has been set by the platform, it said that by mid-March “may be too late”, adding that the 30 day guidance is “sensible”. The amount of time it takes will vary per case and provider.

Foresters Friendly Society: This ‘With Profits’ LISA provider is working to a 6 March deadline.

Hargreaves Lansdown: It has introduced a 6 March midnight deadline.

Nutmeg: At the LISA launch, Nutmeg said it was working on a system to allow H2B ISA transfers to its LISA. However, in November last year, Nutmeg had to u-turn on this, stating that it couldn’t facilitate H2B ISA transfers to its LISA product.

The Share Centre: It’s set a deadline of 29 March 2018 though it recommends customers request a transfer sooner rather than later. “As is the case for all LISA providers, there are no guarantees the transfer will be registered by both parties before 5 April 2018”, a spokesperson said.