That all depends on how old you are, and how far from retirement you are. Who sold those mutual funds to you? Are they inside an Individual Retirement Account, or 40l(k) plan at work? If it’s a retirement account, you could sell half of your funds and move into money market funds INSIDE your retirement account. Then there would be no tax consequences. And if you have at least 20 years before retirement, history says you will come out ahead.
If you’re close to retirement, you might want to sell a greater percentage. But it’s hard to make a recommendation without knowing more about your situation.