Finance and economics are both credible majors for investment banking recruiting. Banks regularly hire students from each, along with candidates studying accounting, engineering, mathematics, computer science, history, and other subjects. Your major is one part of your profile, not an admission ticket or an automatic rejection.
Finance is usually the more directly applicable option. Its courses are more likely to cover accounting, corporate finance, valuation, capital markets, and financial modeling. Those topics overlap with the work bankers perform and the questions candidates receive in technical interviews.
Economics is broader and often more theoretical. You may study how consumers, companies, governments, and markets respond to incentives, while building analytical skills through statistics and econometrics. That foundation is useful in banking, but an economics curriculum may not teach you how the three financial statements connect or how to value a company using comparable companies and a discounted cash flow analysis.