Hi,
I'm not a financial adviser, so these are just my own thoughts and in no way individual advice - Please do your own research.
Looking at M&G itself, the fees seem quite high - minimum £15 per month I think. Depending on how much you have invested that might well affect the performance. Are you also using a Financial adviser? If so they may well be taking a commission on top of that.
Is it an accumulation fund with reinvested dividends, or are you withdrawing the dividends as income from it? This will also affect the growth potential.
The FTSE index fund seems roughly a little under par with the benchmark.
If you look at the photo of the chart I uploaded (Trustnet), You will see over a 5-year period it is just below Vanguard FTSE 100 index tracker (Vanguard likely lower fees).
The main issue I believe, is that since Brexit the FTSE has under-performed compared to many European and US and Global benchmarks. Not just my view but the analysis of many reputable financial publications.
Compare the chart I have uploaded with the Vanguard S&P 500, and the Vanguard Global index fund over the same 5 year time frame of growth:
Vanguard S&P 500 - 79.3%
Vanguard FTSE Global All Cap Index 47.1%
Vanguard FTSE 100 index 20.1%
M&G FTSE All Share Index tracker 16.4%
Looking at 10 year growth
Vanguard S&P 500 289.1%
M&G FTSE Index tracker 63.8%
(the other funds have not been established that long so not displayed)
Now, as all the warnings indicate, past performance is no indication of future growth.
There are risks involved in Global and US trackers - including currency risks.
I would suggest you look at the following:
Your appetite for risk - more risk usually offers greater growth potential but also greater risk of losses.
Fees - can have a significant impact on growth.
Spend more time on researching into investing - use tools such as Trustnet to explore funds, as well as each platforms own Key Information documents.
Read and listen to financial news outlets, journals and podcast/videos. These can be a good source of information on what is happening in the market and trends to be aware of.