Generally, most appreciated assets, such as stocks, real estate, and closely held business interests, can be contributed to a Charitable Remainder Trust (CRUT). However, S-corporation stock is not suitable, and assets that are effectively deemed sold are also not appropriate. For instance, if your company has reached an agreement to be sold with no contingencies to clear or deal points to negotiate, it may be considered already sold. Nonetheless, it is always important to consult with an attorney or tax advisor for specific guidance on your unique situation.