Getty Images; iStock; Chelsea Jia FengMorgan Stanley outlined the investing strategy for investors heading into 2025 this week. Mike Wilson, the bank's CIO, recommended a barbell portfolio for investors to balance risk.He said the economic outlook was mixed next year, with risks swirling around Trump's policies.Wall Street is expecting another positive year for the stock market in 2025 — but there's one investment strategy traders should follow, as the outlook for stocks is more mixed than it appears, according to Morgan Stanley's top stock strategist.Mike Wilson, the bank's CIO and chief US equity strategist, said investors should adopt a barbell investment strategy.