The World Cup has begun, which means investors are once again being offered the usual lists of stocks supposedly set to benefit.“Nike could get a boost”, reads a Barron’s headline. “Fifa World Cup: Deutsche Bank says these are the best stocks to own”, says Yahoo Finance. One Citi analyst came up with a list of 19 stocks, including not only various consumer-oriented names but technology giants Google and Meta. UK investment platform AJ Bell pointed to companies such as InterContinental Hotels, Adidas, JD Sports, ITV and Flutter.This columnist isn’t sure why Google and Meta shares should outperform during the World Cup, but the logic is generally easy enough to follow. Football fans travel, stay in hotels, buy replica shirts, watch television coverage, and place bets, and so invest (or trade) accordingly.Unfortunately, investing is not that straightforward. Long before events begin, bookmakers have modelled betting volumes, hotel groups have assessed demand, sportswear firms have planned campaigns, and all this is already baked into share prices.There’s another problem – the old issue about correlation not being causation. AJ Bell tells us that, historically, the stock market of the World Cup runner-up has outperformed those of both the winner and the host nation. It is a fascinating coincidence, though perhaps not one on which anyone should stake their pension.The moral: enjoy the football, but don’t bother trying to build a portfolio around it.