How Options Adjust After Mergers & Spinoffs

Options adjust after mergers and spinoffs through a formal process at the Options Clearing Corporation, the clearinghouse standing behind every listed US option. It restates what one contract delivers, normally leaves the strike alone, and puts a digit on the end of the symbol. Your position stays valid. What it hands you at exercise changes.

Most people meet this the hard way. A holding that looked ordinary last week now shows a symbol like XYZ1, a deliverable that is no longer 100 shares, and a bid that has gone quiet.

Why your option symbol grew a number

A listed option symbol is four pieces glued together: the root, the expiration date, a C or a P, and the strike padded out to eight digits. Our walkthrough of how to read an options symbol takes each piece apart. An adjustment touches only the first one. XYZ becomes XYZ1 after the first corporate action and XYZ2 after a second, while the plain root keeps listing new standard contracts alongside the adjusted series.

That trailing digit is a warning label. It says the contract carries a non-standard deliverable, and the real terms live in a document rather than in the symbol. Every adjusted series has a memo behind it that spells out what one of its contracts delivers.

How options adjust after a cash merger

In an all-cash acquisition the target's shares stop existing on the closing date. There is nothing left to deliver, so the deliverable becomes money: a fixed cash amount per contract, frozen at the deal price.

Work it through with round numbers. A $50 per share cash deal turns one contract's deliverable into $5,000 of cash. A 45 strike call is then worth exactly $500 at exercise, with no time value left in it at all. A 55 strike call is worth nothing, and no amount of remaining calendar changes that.

The stock announces this long before your position screen does. Activision Blizzard traded under the ticker ATVI until Microsoft closed its cash acquisition in October 2023. Here is the last four months of that tape.

SELECT
    toString(date)                                                             AS session_date,
    concat(monthName(toDate(date)), ' ', toString(toDayOfMonth(toDate(date))),
           ', ', toString(toYear(toDate(date))))                              AS session_label,
    round(max(toFloat64(close)), 2)                                            AS close_px,
    round(100 * (max(toFloat64(high)) - min(toFloat64(low)))
          / max(toFloat64(close)), 2)                                          AS day_range_pct
FROM global_markets.stocks_daily_aggs
WHERE ticker = 'ATVI'
  AND date BETWEEN '2023-06-15' AND '2023-10-20'
GROUP BY date
ORDER BY date

Across 83 sessions between June 15, 2023 and October 12, 2023, the close went from $81.45 to $94.42 and then stopped moving. The high-to-low range on that first session was 1.23% of the closing price. On the final one it was 0.25%. A share that converts into a fixed cash amount on a known date behaves like a short-dated bond.

The options market prices the same thing. Implied volatility is the annualized move an option's price implies for the underlying, and when the underlying has become a cash claim, that number has nowhere left to go.

SELECT
    toString(date)                                                             AS session_date,
    concat(monthName(toDate(date)), ' ', toString(toDayOfMonth(toDate(date))),
           ', ', toString(toYear(toDate(date))))                              AS session_label,
    round(100 * avg(implied_volatility), 1)                                    AS atm_iv_pct,
    uniqExact(ticker)                                                          AS contracts_counted
FROM global_markets.options_greeks
WHERE underlying_symbol = 'ATVI'
  AND date BETWEEN '2023-06-15' AND '2023-10-20'
  AND iv_converged = 1
  AND volume > 0
  AND days_to_expiry BETWEEN 20 AND 45
  AND abs(toFloat64(strike_price) / toFloat64(underlying_close) - 1) < 0.05
GROUP BY date
ORDER BY date

Average implied volatility for contracts within 5% of the money and 20 to 45 days from expiration ran at 29.4% on June 15, 2023 and 7.1% by October 12, 2023. Calls struck above the deal price spend the last months of a merger decaying on a schedule anyone can compute in advance.

How options adjust after a spin-off

A spin-off turns one company into two listed companies. Holders of the parent receive shares of the new one. Option holders are not holders of record and receive nothing directly, so the adjustment is what puts the new company inside the contract.

General Electric distributed one share of GE HealthCare for every three GE shares on January 3, 2023. Run that ratio through a 100 share contract and the deliverable becomes 100 GE shares plus 33 GE HealthCare shares plus cash in lieu of the leftover third. One contract, two tickers.

SELECT
    toString(date)                                                             AS session_date,
    concat(monthName(toDate(date)), ' ', toString(toDayOfMonth(toDate(date))),
           ', ', toString(toYear(toDate(date))))                              AS session_label,
    round(maxIf(toFloat64(close), ticker = 'GE'), 2)                           AS parent_close,
    round(maxIf(toFloat64(close), ticker = 'GEHC'), 2)                         AS spinco_close,
    round(100 * 33 * maxIf(toFloat64(close), ticker = 'GEHC')
          / (100 * maxIf(toFloat64(close), ticker = 'GE')
             + 33 * maxIf(toFloat64(close), ticker = 'GEHC')), 1)              AS spinco_share_pct
FROM global_markets.stocks_daily_aggs
WHERE ticker IN ('GE', 'GEHC')
  AND date BETWEEN '2023-01-04' AND '2023-03-31'
GROUP BY date
HAVING countIf(ticker = 'GE') > 0 AND countIf(ticker = 'GEHC') > 0
ORDER BY date

The third line is the one to watch. On January 4, 2023, the first regular way session for the new company, 26.3% of the adjusted contract's deliverable value sat in the spun-off shares. By March 31, 2023 that share was 26.2%, with the parent at $76.3 and the new company at $82.03. A holder of one adjusted call is now long two different businesses in fixed proportion.

The parent's charted history gets restated around a distribution too, which is a separate trap. Split-adjusted price history covers how those series are rebuilt. Ordinary whole-number splits follow a much simpler path, laid out in how stock splits affect options. This page is the messier family: mergers, spin-offs, cash tenders, and bankruptcies.

What the strike, multiplier and premium mean now

Four things are worth pinning down once an adjustment lands.

• The strike is unchanged as a number, and it is still what exercise costs: strike times 100. It no longer corresponds to a per share price of anything you can look up.
• The multiplier normally stays at 100 for quoting. A premium of 1.50 is still $150 for the contract.
• The premium now prices a package. On an adjusted spin-off contract, that package moves with two stocks at once.
• Exercise delivers the package. A contract finishing in the money hands over whatever the memo lists, which is where what happens if an option expires in the money gets more complicated than usual.

Some adjustments change the multiplier instead of the deliverable, and a few accelerate expiration outright. Only the memo for your contract settles which happened.

Why adjusted options are hard to trade

This is the half that plain definitions leave out. An adjusted series is a one-off instrument with a hand-written deliverable, and the market treats it that way.

• Quotes widen. Fewer market makers price a custom package, and the bid-ask spread on an adjusted series is often a large fraction of the contract's value.
• Many brokers restrict adjusted series to closing transactions. You can exit what you hold; opening a new position in that series is commonly rejected at the order ticket.
• Rolling frequently has nowhere to go. Rolling an option position needs a liquid contract at the new strike or date, and adjusted series rarely offer one.
• The volume simply is not there. An adjusted series draws a fraction of the interest that the standard series on the same underlying does.

Holding one is closer to holding a private agreement than a listed option.

How to find the OCC memo for your contract

Every adjustment is published as an OCC information memo, and that memo is the authoritative record. It names the effective date, the new option symbol, the exact new deliverable, any cash in lieu amount, and any change to the multiplier or the expiration. Search the OCC information memo archive by the underlying symbol, the former symbol, the adjusted option symbol, or the company name, then open the memo whose effective date matches your position.

There is no rule of thumb underneath this. An adjustment panel decides each case under OCC's by-laws: representatives of the exchanges where the option class trades, sitting with an OCC representative. Two deals that look identical from the outside can be adjusted differently. The memo governs.

FAQ

Does an adjusted option keep the same strike price?

Usually yes. The standard method leaves the strike and the 100 multiplier alone and rewrites the deliverable, so a 50 strike call still costs $5,000 to exercise. What that $5,000 buys is whatever the OCC memo lists.

What happens to my options if the company is bought for cash?

The deliverable converts to a fixed cash amount per contract at the merger price. In-the-money contracts settle for the difference between the strike and that amount, and out-of-the-money contracts expire worthless with no path back, since the underlying no longer trades.

Why will my broker only let me close an adjusted option?

Closing-only treatment is a policy applied to non-standard series with unreliable liquidity. Existing holders can exit, while new opening orders in that series are typically blocked. The restriction sits on the series, not on your account.

What happens to listed options when a company goes bankrupt?

The contracts follow whatever the shares become. If the stock keeps trading over the counter, the deliverable is generally restated to those shares. If the shares are cancelled with nothing distributed, the deliverable can be worth nothing while the contract still exists. OCC can also accelerate expiration, and the memo states which path was taken.

Every panel above ships with the SQL that produced it. To trace a deal pinning to its close, or watch a spin-off split one deliverable in two, ask it in plain English on the Strasmore terminal.