Offer your thoughts or opinion on the input financial query or topic using your financial background.

Is it smart to only invest in mid- and small-cap stock equity funds in my 401(k)?
Can you easily stomach the risk of higher volatility that could come with smaller stocks? How certain are you that the funds wouldn't have any asset bloat that could cause them to become large-cap funds for holding to their winners? If having your 401(k) balance get chopped in half over a year doesn't give you any pause or hesitation, then you have greater risk tolerance than a lot of people but this is one of those things where living through it could be interesting. While I wouldn't be against the advice, I would consider caution on whether or not the next 40 years will be exactly like the averages of the past or not. In response to the comments: You didn't state the funds so I how I do know you meant index funds specifically? Look at "Fidelity Low-Priced Stock" for a fund that has bloated up in a sense. Could this happen with small-cap funds? Possibly but this is something to note. If you are just starting to invest now, it is easy to say, "I'll stay the course," and then when things get choppy you may not be as strong as you thought. This is just a warning as I'm not sure you get my meaning here. Imagine that some women may think when having a child, "I don't need any drugs," and then the pain comes and an epidural is demanded because of the different between the hypothetical and the real version. While you may think, "I'll just turn the cheek if you punch me," if I actually just did it out of the blue, how sure are you of not swearing at me for doing it? Really stop and think about this for a moment rather than give an answer that may or may not what you'd really do when the fecal matter hits the oscillator. Couldn't you just look at what stocks did the best in the last 10 years and just buy those companies? Think carefully about what strategy are you using and why or else you could get tossed around as more than a few things were supposed to be the "sure thing" that turned out to be incorrect like the Dream Team of Long-term Capital Management, the banks that were too big to fail, the Japanese taking over in the late 1980s, etc. There are more than a few times where things started looking one way and ended up quite differently though I wonder if you are aware of this performance chasing that some will do.