[cryptica]

This is not a good idea because with shorts you need to time the market correctly... Irrational markets can survive for years and shorts cost premiums, especially those with a distant expiry date. If you're not a stock analyst with inside info, you will not be able to get the timing right.

[aeternus]

If you are concerned about timing it right, or macro-economic swings, simply purchase a corresponding long position in an index fund / S&P 500. Options do cost premiums, but shorts typically do not. You can however even recover the option premium with a similar strategy by selling a matching option on the index.

You can construct a trade that will make you money assuming your assumption is correct (that that company will underperform the market).