Option Selling Capacity and Dealer Absorption

Large institutions — pension funds running covered-call overlays, insurers hedging variable annuities — sell enormous volumes of options as a matter of routine business, not opportunistic trading. Someone has to be on the other side of every one of those trades, and in practice that's usually a bank or market-making dealer. But a dealer's ability to keep buying that flow isn't unlimited.

When a dealer buys a put from an institutional seller, it typically hedges by shorting some amount of the underlying stock (delta hedging) and continuously adjusts that hedge as the price and time-to-expiry change (gamma exposure). Absorbing a small flow of such trades is routine. But when persistent, one-directional selling — like month-end overwriting programs rolling large notional at the same time every month — pushes a dealer's book heavily net-long puts, the dealer's own hedging activity can become large enough relative to the underlying's typical trading volume to move the market, at which point the dealer starts pricing in that impact by quoting worse levels rather than absorbing the flow at the same price.

This dynamic is one reason large systematic options overlays are watched closely by market strategists: when known monthly rebalancing flows are large relative to dealer absorption capacity, the resulting hedging activity can itself become a predictable, tradable pattern around expiry dates.