Without knowing all the details, there are a few reasons that explain the outperformance: - long bull market lower the probability of achieving results above m

Without knowing all the details, there are a few reasons that explain the outperformance: - long bull market lower the probability of achieving results above market, especially if the performance is concentrated in a select group of stocks/industries - not knowing the factors in detail, but you might not have a period long to assess the performance. Factor performance tends to be attached to "performance regimes" - the factors you considered in the past were underpriced, and in your evaluation window they are no longer in such state, so expected returns are lower - market has catched up on the factors that you are using (your "free lunch" has been eaten). I guess there's a reason why nowadays quants freely join podcasts while a few years ago we had to be very careful in interviews ("do they want to hire me or do they just want to know what I'm doing/not doing")