Following up on the 15 minute market deep dive, we are now seeing a similar structure emerge in the newly launched 5 minute BTC markets by @Polymarket. For those asking why traders would use 5 minute contracts instead of perps with tighter spreads, that is the wrong comparison. These are not directional products. They are capital recycling products. In 40 hours since launch, 5 minute markets have already generated $25.2M in volume. Average volume per window is ~$52K, already 10%-20% of 15 minute market turnover. That is meaningful for a product this early. Participation data confirms what we saw in 15 minute markets. 7.1% of unique addresses have bought both Yes and No within a single window. Only 4.2% have done this across more than 50 windows, meaning the full scale systematic cohort has not yet entered in size. Yet despite being few in number, these addresses already account for 7.5% of total volume and 23.4% of all trades. That imbalance tells us they are placing many small, tight orders competing for marginal spreads. Their profile looks familiar. 92.6% of their flow is buy side and 72.3% is maker volume. They are profitable in 80% of windows with a median Yes plus No price of $0.9823. This is early stage arbitrage behavior. What is missing so far is the large scale supply injector we observed in 15 minute markets. If that structural liquidity arrives, I expect 5 minute market volumes to scale rapidly and eventually surpass 15 minute markets, just as 15 minute markets overtook hourly ones. A smart move from Polymarket.