CSPX or VUAA for S&P500 Accumulating ETF?

I will invest in CSPX due to the fact that it has more trading volume

They both track the same index, both list in the same exchange and are traded in the same currency. Both of them also automatically reinvest dividends. Expense ratios are also the same.

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Their performance will be virtualy identical. The main consideration would be the fund size. CSPX is much larger than VUAA, hence bid-ask spread should in theory be lower. However CSPX is trading at a much higher price, which may be a consideration due to the fact that brokers usually do not support fractional shares for UK markets.