One option for adding shares.Encyclopædia Britannica, Inc.If you’re familiar with option basics, you know that a put option contract gives the owner (i.e., the buyer) the right, but not the obligation, to sell 100 shares of the underlying stock or ETF at a specific price (the “strike” or “exercise” price) by a certain date (the option’s “expiration date”). The premium is what you pay for that right. And as the seller of a put option, you have the obligation—at the owner’s discretion—to buy the underlying stock or ETF at the strike price. In order to accept that obligation, you’re paid the premium.

　　Selling put options can be risky. If the stock’s value drops significantly—or even becomes worthless—you could face substantial losses. Of course, that’s the same risk you take when buying shares of a stock. But it’s the rationale behind the stock accumulation strategy, a way to use short put options to let you “get paid” (via option premium) to wait for an opportunity to buy a stock or ETF you’re considering at a certain price below where it’s trading today.

　　Unless you’re a high-volume trader with money in a margin account (i.e., one that allows you to trade with borrowed money), when you sell a put, your broker will require you to hold enough cash in your account to cover a stock purchase if the owner exercises their option. That’s why it’s called a cash-secured put. 

　　Selling put options: A stock accumulation strategySuppose there’s a stock on your wish list that’s currently trading at $50 a share. You like the company, but the stock has rallied recently and $50 is a little rich for you. Still, if shares were trading 10% lower—at $45 a share—you’d like to own 100 shares.

　　What if you could get paid to wait for an opportunity to potentially buy it at $45 a share? You can do that by selling a put option at the $45 strike.

　　You’ll collect the premium up front, and if the stock stays above $45 until the expiration date, you’ll pocket that premium. If the stock sinks below $45, you’ll be assigned a long position at $45—your target entry point. And here’s the kicker: Your effective acquisition price (cost basis) is actually below $45 because of the premium you collected up front:

　　Remember: when you sell a cash-secured put, your broker will require you to keep enough money in your account to cover the purchase of the stock if you’re assigned the put option. Because you’d be acquiring 100 shares at $45, but you collected $200 up front, you need to have an extra $4,300 on hand (see figure 1).

　　Figure 1: SELLING PUTS FOR STOCK ACCUMULATION. With the stock at $50, if you sell a 45-strike cash-secured put for $2, you'll be assigned a long position of 100 shares at $45 if the stock falls below that price. But because you took in $2 of premium, you're essentially acquiring the stock at $43. If the stock stays above the strike, you pocket the $2 premium and have no position in the stock. For educational purposes only. Encyclopædia Britannica, Inc.Stock accumulation vs. stock acquisitionWhy is it called “stock accumulation,” considering the example shows how to acquire a stock that’s deemed too expensive to buy outright at the prevailing price? It’s because many investors use the cash-secured put strategy to slowly add to stock positions they already hold.

　　For example, suppose you’re a long-time shareholder of Apple, Inc. (AAPL), and you wish you had bought more along the way. What you might not have realized is that, despite having made new all-time highs consistently through the 2010s and early 2020s, Apple shares routinely experience temporary drops in price, or pullbacks, of 10% or more (see figure 2).

　　Figure 2: CATCH A FALLING APPLE? Few stocks have matched the performance of Apple, Inc. (AAPL) in the 21st century. But for investors looking to accumulate more shares on a pullback, even the mighty Apple has offered opportunities.Source: Stockcharts.com. Annotations by Encyclopædia Britannica. For educational purposes only. Past performance does not guarantee future results.An Apple shareholder who routinely sold put options at strike prices set 10% to 15% below the current price would have continued to enjoy long-term capital appreciation in the stock, consistent premium collection as put options sold during rising (and stagnating) markets, and would occasionally accumulate more shares during market pullbacks.   

　　The risks of selling cash-secured putsAs with all option strategies, selling put options—even when you’re limiting yourself to cash-secured puts—involves risks and trade-offs that must be considered:

　　Big drawdowns. When you sell a put option, you’re agreeing to take a long position at the strike price. And if you already own shares, a precipitous fall in the share price is a double whammy, because you lose on both the put option and your existing shares. But if you’re committed to the company’s long-term profitability, it may be a risk worth taking. No dividends on stock you don’t own. Some traders will play the targeted put-selling game but never actually accumulate shares. They might roll their positions (i.e., buy back the short put and sell a put at a different strike and/or deferred contract month) as markets move and time passes. And although they might be profiting from premium collection, they don’t get to participate in any dividends paid by the company. Opportunity cost. When you sell a cash-secured put, you’re required to keep cash in your account to cover a potential share purchase. By holding cash, you’re giving up the opportunity to put that money to use elsewhere—another stock, bond, real estate, or other asset you might otherwise put the money toward.The bottom lineOption selling isn’t for everyone, particularly when it involves unquantifiable risk. That’s why brokers put restrictions on selling uncovered (aka “naked”) options in non-margin accounts, but allow covered calls and cash-secured puts.

　　There’s another way for premium sellers to keep their basic strategies intact, but turn unquantifiable short options into a defined-risk strategy. Vertical spreads involve selling a call or put option for a credit and simultaneously purchasing a long call or put option with the same expiration date, but further out of the money. You’ll receive a net premium when you initiate the trade, and your overall risk is limited to the difference between the short and long strikes.

　　With cash-secured puts, it’s possible to target specific stock accumulation targets and get paid while you wait patiently for those targets to come to fruition. But if you want to define your risk parameters and sidestep the cash-secured requirement, learn how to set up and execute a put vertical spread.