Can I deduct lost equity in a country club that went bankrupt?

Yes, you generally can deduct an investment loss. You will enter this as an investment SALE. See the screenshot below.

You can deduct the investment in the tax year it becomes completely worthless. This normally happens when the corporation files for bankruptcy, stops doing business, and has no assets. Financial difficulties won't make it worthless unless there is no hope that the company will pull through.

Enter a worthless investment with a sales price of zero and the word "worthless" in its description. Enter the correct cost or basis, date acquired, and December 31 as the date sold.

Non-security investment sales like coins, collectibles, timber, land, or a second home are entered as follows:

1. Open (continue) your return in TurboTax.
2. In the search box, search for investment sales then click the "Jump to" link in the search results.
3. Answer Yes to the question Did you sell any investments?
   • If you land on the Here's the investment sales we have so far screen, click Add More Sales.
4. Answer No to the 1099-B question.
5. On the next screen, select the type of sale you had (second home, collectible, land etc.) and click Continue.
6. Continue following the onscreen instructions to enter the sale.

NOTE: The above entry instructions work for Worthless Stock, also.