"iShares Core FTSE 100 UCITS ETF GBP (Acc)" is an exchange-traded investment fund (ETF). It refers to the FTSE 100 Index. This index reflects the development of 102 British stocks and is therefore relatively well diversified. The ETF replicates its index using full physical replication, so it contains all the securities of its reference index. The ETF's earnings (dividends) are automatically reinvested (accumulated). The fund company iShares claims a total expense ratio (TER) of 0.07% per year. The yearly average divergence from the index performance (Tracking Difference) since 2011 was 0.15% per year. Therefore, the ETF was more expensive than the TER suggests.
Comparing Tracking Difference, Total Expense Ratio and fund size
Every bubble represents an ETF. The further to the right it is, the higher (worse) is its tracking difference. The further up it is, the higher the total expense ratio specified by the fund company. The bubble's area represents the fund volume.