Bitcoin (BTC) futures open interest is mimicking the start of the BTC price bull run, data shows.

As BTC/USD hovered near $40,000 on Thursday, a fresh bullish report from Stack Funds called for “cautious optimism” about further price rises.

Bitcoin has sought to flip $40,000 to support this week, returning to the level multiple times and refusing to leave recent gains as a blow-off top.

According to its latest weekly market appraisal, however, Stack Funds believes that it is derivatives that are giving stronger hints about potential bullish price continuation.

Bitcoin open interest is currently exhibiting the style of increase that characterized Q4 last year — the springboard for current $64,500 all-time highs.

“Those who wanted to accumulate lower might have missed out on the large swings, but fret not; re-adjusting your entry levels could reap you a more significant return on the bigger picture of this super cycle,” the report states.

This Friday, meanwhile, sees the end-of-month expiry event for Bitcoin options, something that — at least in theory — allows for a release of potential selling pressure thereafter.

Stack continued that given recent events, regardless of short-term price strength, a return to fresh lows near previous all-time highs of $20,000 was “less likely.”

Related: Bitcoin fails to flip $40K with traders eyeing $36K or lower for support

On the flipside, resistance bands as yet untouched remain a dark cloud on the immediate horizon for bulls.

“There are also several major resistances ahead; such as the $41,000 resistance level, which coincides with July’s 1.618 Fib, and also the $45,000 daily 200MA level,” the firm added.

“Only when a clear break occurs, then we can safely say the Bitcoin trend has reversed.”

Order book data from major exchange Binance highlighted a high resistance band concentration in the area above $41,000.