S&P 500 performance differs from my portfolio even though I only invest in S&P 500 ETFs

S&P 500 performance differs from my portfolio even though I only invest in S&P 500 ETFs https://preview.redd.it/56s2yos30ioh1.png?width=1515&format=png&auto=webp&s=6e5804a4479b1c0218a375ae74397061d98bc84c Hello everyone, I started investing a few months ago, and so far I've only invested in SPYL.L (SPDR S&P 500 UCITS ETF Acc). My intention is simply to track the S&P 500. However, when I look at the performance chart in the IBKR dashboard, there seems to be a fairly large difference between my portfolio's performance and the S&P 500 benchmark, this is more than 2 percentage points. This seems strange to me because SPYL is designed to track the S&P 500. Shouldn't my portfolio's performance be roughly the same as the S&P 500, aside from small differences such as fees and tracking error? For example, the IBKR chart currently shows approximately: My portfolio: +2.04% S&P 500: +4.13% Difference: \~2.1 percentage points I understand that there may be factors I'm overlooking, such as currency, cash sitting in the account, the way IBKR calculates TWR, or differences between the benchmark and the ETF's actual return. I'm still relatively new to investing, so I'd really appreciate it if someone could explain what might be causing this difference. Is there something about IBKR's performance calculation or SPYL that I'm misunderstanding? Thanks!