A bad month?

ZOPA should provide guidance on the size of investment and the timescale, to achieve their expected returns. I expect your investment is too small and too short to achieve those returns. ZOPA really ought to provide guidance on these issues.

At one extreme 100 loans of £10  over one year are unlikely to return the same result as 8000 loans of £10 over a five year period.

I don't believe in bad luck. Something is wrong.

amphoria's chart is very close to what I have on my loans. Although my only month in 2017 without losses was April.
I started my Zopa account in 2012 and built it up slowly till 2015
£9k of my £11k is in Plus and I have it set up to reinvest in Plus, so not easy to dis-aggregate them . 

Of the return I should have received in 2017 to end July 46% has been defaulted.
The 2017 return on Plus is still a whisker over 4%!
I too am considering stopping reinvestment in Plus- however I fear it is too late as the defaulting loans were made some while back. All my defaults, bar 1, were in 2017
Cars 6                                  all started 2015 -2016
Consolidate existing Debt 17  all started 2016
Credit Card 2
Holiday 3
Home Improvement 10          all started 2015 -2016

The impending change to Core with an expected return of 3.9% probably only recognises the position that I am at present with Plus. It merely removes the concept of a 6.1% return that now seems hopelessly optimistic judged by the performance of my Loan Book over the last 7 months.

Very nice graph, amphoria, but to be fair it would look less alarming if the XIRR axis went to zero.

Were they at Cow's week too?

Whilst on board a Sunse'e'eker just to make the "trip" more interesting!!

Of course the graph is fine and I didn't mean to imply you were attempting to mislead. I just thought I'd mention it for the benefit of any other slow folks like me who initially got a fright.

Not necessarily sometimes people can be in arrears for the first 2/3 months until payments get aligned. Check the comments fields as well as the arrears amounts.

Also check the status column if its set to Collections it could be of concern. I've just checked mine and I have 3 that are new loans but they seem to be slipped or mismatched initial payments as they are still marked withdrawn, hopefully they will level out. If they are showing defaults then it's a bit more of an issue but still not damaging.

Also you should check if they are marked as SG in Classic, even in ISAcore they can be SG protected. If they are then you don't need to worry about them as they will be settled eventually by the SG fund (Well that's the theory at the moment ;-))

I'm sure you already know, but just in case, loans in arrears have to wait at least 4 payment periods (months) before the loan is marked as defaulted.

Hopefully yours are not as bad as they look. In my case I have mostly old Pre-SG defaults and most are still paying, slowly but still paying. Thats not to say that this time arround they will fair better or worse though.

edit: Oops the above is more general I've just noticed you said they were in Plus so the SG bits above don't count. The status and comments field though do count.

The one other thing to be aware of is rate of default - I have found the statements to be quite helpful in showing the default hits. Mine have been quite good to me so far as I said and my gains in any month are higher than the defaults - they have been in drips for me so far so I guess i've been quite lucky.

I've got 2 defaults in 177 loans in plus - 1 is in difficulty and the other has made one initial payment since the start in Jan and has just gone to default last month. I have 5 collections but 3 of them look like they are just misaligned after missing one or recovering completely. The other may not get better. My Plus lending started around June last year. Each persons lending experience will be different but hope this helps