Prosper Avis 

This ISA was on Martin Lewis' site. That was good enough for me. And since everything has been good.

Opening account & setting up a wallet was a straight forward process & at the time of depositing funds had market leading interest rates. Would of liked the option of online access to my account not just app only which this is but I was aware of that before opening my ISA.

Great rate, but the app is very confusing.
My money went in to the wallet then trying to transfer it to a cash ISA wasn't easy and took several attempts doing it from different screens before it worked. The app needs work.

Day one read about Prosper and opened account.
Day two opened ISA and transferred funds.
Very quick, very efficient and with excellent rate of interest.
Very happy.

I found the website straight forward to set up my investment.

I am very impressed following the transfer of my S&S ISA to Prosper last month. Requesting transfer to completion was a matter of days (unlike some larger providers, with whom I've experienced considerable delays) and customer service helped a lot. I've now transferred in a small SIPP which has also gone well.

Investing is easy through the mobile app, and there is a reasonable list of passive funds.

For me, what really sets Prosper apart is the zero fee index funds, which I've not seen offered elsewhere (only for ETFs). It's obviously also a great bonus that a small number have fees refunded. The cash ISA has a fantastic rate, though I haven't opened this yet.

If I could offer any suggestions it would probably be more offerings from UK and European fund managers; for some of these to be in the funds with refunded fees (which appears to only include US managers); more ESG funds, especially global ESG funds; and automated regular investments. But overall everything has been great and I would highly recommend!

I’ve opened so many accounts in my lifetime as I always chase the highest interest but honestly this was the easiest I’ve opened. 5 minutes, the ISA was opened and all funds transferred from my linked account.

Like the app, easy to use and the lowest fees out there. Looking forward to more functionality being rolled out.

Easy transaction, helpful information and communication, good returns.

I Opened my isa through the app. It was really easy and straightforward. ( although I had to help a friend do theirs as they had transferred the cash through the app but you still need to move it from the Wallet to the ISA). It needs a bit more explaining (as they were about to move the cash back and close the app. !) good job I helped out.
So far I’m happy with it though.

Good easy working online company, no trouble at all.

Absolute fiasco dealing with prosper that has cost me my 2025 to 2026 ISA Allowance. Ive never dealt with a more incompetent financial organisation.
I opened an account with Prosper and applied for their cash ISA, with the intent of putting in 20k as per the 2025 to 2026 allowance.
I did all the biometrics and waited for them to validate the account. The account was validated around 3 days later on the last day of the tax year April 5th. I transferred 20k into my wallet in the app. I then clicked on ISA. I transferred the 20k into the ISA. Meanwhile my partner also interested in making a deposit was applying and discovered the cash ISA was closed, and I said good job I got in when I did, just made it.
But no. My money was sequestered to their stocks an shares ISA, that I most certainly didn't want and hadn't applied for!
I immediately withdrew the 20k back to my wallet only to be told it would take 3 days! Money transferred in in a few minutes, 3 days to get it back, in fact it took 5 days to appear in my wallet. So I lost the chance to take advantage of the 25 to 26 ISA allowance. I have also lost 6 days interest on my 20k.
Their response has been abysmal. From raising a query expect to wait 3 days for a reply.
Ive made an official complaint, and have heard nothing, zero.
Don't touch this company with a barge pole, and certainly don't trust them with your money.

Edit following their response.

I applied for the CASH ISA on 3rd April when I also submitted my biometrics! And was told to await validation, which was confirmed on the 5th April and a request to resubmit biometrics. Obviously on the 5th you didn't want to give me a cash ISA so I suggest you cancelled my 3rd April application and in asking for "updated biometrics" you were able to make it appear i joined on the 5th. The subterfuge was in the app just stating "ISA" NOT "Stocks and shares ISA" so I reasonably expected it to be the cash ISA I'd applied and seemingly been accepted for on the 3rd.
I now have my money back having lost interest on it while it was with you, and the ability to lodge those funds in a Cash ISA under the 2025 to 2026 allowance.
Ive since read the one star reviews and it speaks volumes about you.

Very easy to set up your ISA account and the app is very clear and simple to use.
Good interest rate so “so far so good”.

Very easy and simple process, paying a good rate, handled efficiently. No complaints so far!

Very easy to set up a new ISA, simple semiautomatic process.

All good so far with my Csh ISA

5* for the rate

4* for the experience. Personally the whole transfer into wallet and then into ISA felt clunky and I assume this will be the same with withdrawals.

Onboarding had an issue trying to auto verify my details first through open banking and then through statement PDF upload (although Starling will be partially responsible here).

The AI chatbot that powers customer service wasn’t the most helpful but like the way it creates a manual ticket after you hassle it enough.

Simple, effective, transparent.

VERY low cost, and a great curated selection of funds. For the price, much more worthwhile than HL, ii, moneybox or 'trade-anything' platforms. Gets access to the right solutions in the best way and longer term saving.

Very easy to open an account and offering very competitive rates for savings

Easier to use than most apps, and great rate too