You are trading in a market in which you know there are a few highly skilled traders who are better informed than you are

a)

UNDERPERFORM

You will remain underperform till the time you don't have the required information or someone has more information that you carry . although there are few highly skilled traders but it doesn't matter , in actual market there are few skilled traders and rest are speculators, therefore the skilled ones earn more because they know more .

markets in this case are semi-strong efficient

Semi-strong form efficiency contends that security prices have factored in publicly-available market and that price changes to new equilibrium levels are reflections of that information. It is considered the most practical of all EMH hypotheses but is unable to explain the context for material nonpublic information (MNPI). It concludes that neither fundamental nor technical analysis can be used to achieve superior gains and suggests that only MNPI would benefit investors seeking to earn above average returns on investments.

therefore they know the information that is not readily available and make money out of it and you will remain underperfoemed

b)

SAME RETURN

IF ALL THE MARKET PARTICIPANTS KNOW EQUALLY ABOUT THE INFORMATION IN THE MARKET THEN YOU WILL MAKE EQUALL MONEY AS EVERY OTHER PARTICIPANTS BECAUSE INFORMATION AVAILABLE TO YOU IS SIMILAR TO ANY OTHER PERSON AND AS SOON AS THE NEWS WILL COME OUT EVERYBODY WILL REACT TO IT TILL THE PRICE OF SECURITY REACHES EQUILIBRIUM

THIS IS KNOWN AS STRONG FORM EFFICIENT

The strong form version of the efficient market hypothesis states that all information—both the information available to the public and any information not publicly known—is completely accounted for in current stock prices, and there is no type of information that can give an investor an advantage on the market.

Advocates for this degree of the theory suggest that investors cannot make returns on investments that exceed normal market returns, regardless of information retrieved or research conducted.