Where would you invest $1K to $5K to get the maximum rate of return?

Further explanation of the question (from Quora): I am looking to get a return of 10% or more on my investments and taking calculative risk is not an issue.

My answer: Maximum rate of rate of return means two things - you want the highest return and in the shortest time. The answer to that question is - gambling. One a more serious note - 10% in what time frame and in which country?

For a developing (high inflation) country like India:
10% in a year is easy for developing countries. A lot good companies (say in manufacturing or infrastructure) raise money via commercial bonds. They are safe and give decent returns. I invested in Tata Motors 4 years back and it gave me a return of 35.79% in 3 years. Sriram Finance keeps coming up with good options.

For 10% quarterly or monthly, your risk will have to be higher. You will then have to invest in stocks that qualify as "high beta" or make some out of the ordinary choices. I usually filter out stocks based on my interest areas (or sectors) and fundamentals indicators. I enter and leave (open and close positions) based on technical indicators. The other option is investing in futures & options. I don't recommend writing options (or futures of any kind), if you don't have a good understanding in capital markets.

For developed  (low inflation) countries:
10% year-on-year is decent but not a huge challenge. You should pick a set of solid stocks with good fundamentals and invest in the ones that "seem" to be under-priced (comparing PE can be a starting point). If you spend a little bit of time by studying the business cycles (every industry has certain patterns) then you have a better probability of succeeding.

For 10% monthly or quarterly, it is kind of a big deal and you will have to play with high-beta stocks or derivatives. You could also do what hedge funds do - go long and short at the same time (on different stocks obviously).

In any case if you don't have the time to sit and analyze, just buy 3-4 good stocks that "seem" to be under-priced and sit on them for years. I can't recommend any small business investing because $1000 to $5000 is too little for that.