Bitcoin bulls are waiting ahead of a massive batch of options contracts headed toward expiry, with roughly $15 billion in bitcoin options set to expire on Friday as part of the market's quarterly settlement — one of four such events each year, when contracts written for the end of the quarter expire together.

The September 25 contracts account for more than a third of all bitcoin options open interest — the total number of contracts still outstanding — on Deribit, the crypto derivatives platform where the contracts are listed.

A call option gives the trader the right, but not the obligation, to buy the underlying asset at a set price on a future date. A put option gives the right to sell. That set price is known as the strike.

Traders appear to be leaning bullish heading into Friday. The put-to-call ratio, a closely watched gauge comparing bets to sell against bets to buy, sits at 0.70, meaning more traders are positioned for prices to rise than for them to fall.

The biggest piles of call options are stacked at strike prices of $85,000, $90,000, and $100,000 — with the round-number $100,000 strike, the highest of the three, a marker of where the bullish bets cluster.

Bitcoin's price was recently trading at around $84,258, down 2% over the past 24 hours and well above the so-called max pain level of $76,000. Max pain is the price at which the largest number of options contracts would expire worthless, causing the most losses for option holders. Bitcoin sits just below $85,000, where call options are most heavily concentrated — calls are said to be "in the money" when the asset trades above their strike — and traders are watching whether that level caps prices ahead of Friday's expiry.

When a large batch of options nears expiry, crypto markets can become more volatile as traders decide whether to close their positions, roll them into later contracts, or let them lapse. Past expiries have sometimes been followed by sharp price moves in either direction, and on occasion large expiries have been followed by market crashes. That outcome is not a given, however, as market makers hedging their books can dampen price swings in the run-up to settlement, sometimes suppressing volatility by selling option premiums and keeping prices close to heavily traded strike levels.

Investor interest in Bitcoin has been renewed after the artificial intelligence stock rally cooled and the U.S. Department of the Treasury said in August that it would at least double the size of its liquidity-support buyback operations. Analysts said the move pushed 30-year Treasury yields — a benchmark for long-term borrowing costs — down, weakened the dollar, and made assets like bitcoin more attractive. Following the announcement, the bitcoin price had its best run in years.

According to a Tuesday report from crypto market data firm CryptoQuant, the leading cryptocurrency has crossed above its 365-day moving average — the average price of the past year — a signal, the firm said, that the asset has finished being in a bear market.

This article first appeared on Bitcoin Magazine and is written by Mathew Di Salvo.