In tax lingo, an asset can appreciate two ways:
Some assets appreciate both ways such as a valuable office building. Its tax basis will be depreciated generally over 39 years and its true value may be increasing (finally, after some tough times). If you put appreciating assets in a corporation, you are making one of your biggest partners the IRS. Thus, you should never contribute to or acquire appreciating assets in a corporation. This advice has been critical since the mid-80's, but the problem is still prevalent.
Although a regular ("C") corporation is the worst entity for appreciating assets, even an S corporation is markedly inferior to a tax partnership (such as an LLC). If you have appreciating assets stuck in a corporation, the sooner you address the problem, the better. Also, remember that some appreciating assets are easy to miss like goodwill and going-concern value. Someone who truly appreciates assets will put them in tax partnerships.