Since the summer, the market has seen tremendous gains, powered along by companies like Netflix (Nasdaq: NFLX) ramping up as much as 100% from the end of July, Chipotle Mexican Grill (NYSE: CMG) shooting up a similar amount since mid-July, and Harvest Natural Resources (NYSE: HNR) up, you guessed it, 100% since the end of August.

After runs like that, Jim Cramer might have you sell half to take your original investment off the table. That leaves just the "house's money" at risk.

I dislike the concept of the house's money, because it sets up the wrong mind-set for investors. In particular, that mind-set leads to the belief that it is somehow "OK" to lose that remaining investment and that you haven't somehow earned it.

Investors are ill-served by that mind-set, as it interferes with them fully benefiting from doubles, triples, or even the elusive 10-baggers.

For my full thoughts on the concept of the "house's money," click to play the video below.

Chipotle Mexican Grill is both a Motley Fool Hidden Gems and a Rule Breakers pick. Netflix is a Stock Advisor recommendations. The Fool owns shares of Chipotle Mexican Grill and Harvest Natural Resources. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors.

Analyst Jim Mueller owns shares of both Netflix and Chipotle. He works for the Stock Advisor newsletter service. The Fool's disclosure policy was written by the house, but hopes you won't hold that against it.