But I'm also a big fan of the Stocks and Shares ISA. ChatGPT pointed out that both wrappers let investors buy shares, funds, and exchange-traded funds without paying capital gains tax. A SIPP gives investors an immediate tax boost through tax relief on contributions. A SIPP gives your savings a massive upfront boost, with all growth on top. One thing I wouldn't do is ask ChatGPT to choose my underlying SIPP and ISA investments.