Covered Call

At expiration the position resolves into a simple piecewise payoff. Below the strike the call expires worthless and the investor keeps the shares plus the premium; above the strike the shares are effectively sold at the strike, so total proceeds stop rising. Breakeven is the purchase price of the underlying minus the premium received, because the premium lowers the effective cost basis. Maximum gain equals the strike price minus the purchase price, plus the premium; it is reached at any price at or above the strike. Maximum loss is the purchase price minus the premium, realised only if the underlying falls to zero.

The asymmetry is the whole point. Downside exposure remains almost fully intact and is merely reduced by a fixed cash amount, while upside is truncated at a hard ceiling. The strategy therefore expresses a neutral to modestly bullish view, not a bullish one.

Selling a call subtracts its delta from the long underlying position, so a covered call always has positive but reduced delta. Writing deep out-of-the-money calls removes little delta and little premium, keeping the position close to outright ownership. Writing at-the-money calls captures the largest time value and produces the greatest volatility dampening, but caps gains immediately. In-the-money writes behave almost like a pre-arranged sale with a downside buffer.

The overlay is short gamma, short vega and long theta. The writer profits from the passage of time and from realised volatility coming in below the implied volatility embedded in the option price; that harvested volatility risk premium is the economic source of the strategy's income. When realised volatility spikes, the short gamma works against the writer precisely when the underlying is also falling.

Institutional use falls into two camps. Systematic buy-write and income funds sell index or single-stock calls on a rolling schedule to convert expected capital appreciation into distributable cash flow, which is why option-income ETFs typically post high yields alongside muted total returns. Discretionary overwriting is used by portfolio managers around a target sale price, and by holders of concentrated or restricted stock seeking monetisation without an outright sale.

With American-style single-stock options, early assignment matters. A holder of a deep in-the-money call may exercise on the day before an ex-dividend date to capture the dividend, forcing the writer to deliver shares earlier than expected. Index options are usually European and cash-settled, so this risk does not arise. Transaction costs, rolling costs and the tax treatment of assignment can materially erode the theoretical premium income.

Expect to construct the payoff and profit diagram from scratch, identify the kink at the strike, and compute breakeven, maximum profit and maximum loss from a purchase price, strike and premium. Expect also to compare outcomes at several terminal prices against simply holding the underlying, and to state the price range over which the covered call outperforms.

Equally testable is the structural relationship to other positions. Long underlying combined with a short call has the same terminal payoff shape as a short put, which follows directly from put-call parity rearranged. Candidates should be able to state the investor view that justifies the trade, distinguish it clearly from a protective put, which buys insurance rather than selling it, and explain why a collar combines the two: the call premium funds the protective put.