Key Takeaways
- Allows underwriters to sell 15% extra shares.
- Stabilizes stock price after IPO.
- Underwriters cover shorts by buying shares.
- Boosts investor confidence and reduces volatility.
What is Overallotment: Definition, Purpose, and Example?
Overallotment, also called a greenshoe option, is a provision in underwriting agreements allowing underwriters to sell up to 15% more shares than the original offering amount. This mechanism helps stabilize the stock price after an IPO by managing supply and demand dynamics.
By using overallotment, issuers and underwriters work together to reduce price volatility, protect against market fluctuations, and support investor confidence. This is especially relevant when companies raise capital through share sales that impact paid-in capital.
Key Characteristics
Overallotment features key attributes that make it a vital tool in equity offerings:
- Greenshoe option: Allows underwriters to sell up to 15% additional shares beyond the planned offering.
- Price stabilization: Helps manage post-offering price volatility by balancing supply and demand.
- Short position creation: Underwriters initially sell extra shares short, creating a controlled obligation.
- Limited scope: Typically capped at 15% to comply with regulatory and market standards.
- Underwriting agreement: Included as a clause in contracts between issuers, underwriters, and sometimes vendors.
How It Works
Underwriters begin by selling more shares than the issuer initially planned, usually up to 115% of the offering size, which creates a short position. This short position gives underwriters flexibility to manage price movements in the market.
If demand is strong and share prices rise above the offering price, underwriters exercise the overallotment option by buying additional shares from the issuer at the offering price, closing their short position without loss. Conversely, if prices fall, underwriters cover their short by purchasing shares in the open market at lower prices, profiting on the difference while supporting the stock price.
This process reduces the risk for both underwriters and issuers, ensuring a smoother trading debut and less volatility in the early market stages. Understanding this mechanism is crucial if you invest in IPOs or track companies like Bank of America or JPMorgan Chase that often participate in underwriting activities.
Examples and Use Cases
Overallotment provisions are common in IPOs and other equity offerings, providing practical benefits to issuers and investors alike.
- Financial institutions: Underwriters such as Bank of America and JPMorgan Chase frequently use overallotment clauses to stabilize new issues.
- Stock offerings: In an IPO where 10 million shares are issued, an additional 1.5 million shares may be overallotted to manage demand fluctuations.
- Price stabilization: When a stock price rises after the offering, the greenshoe option allows purchasing additional shares from the issuer, preventing excessive price spikes.
- Market support: If prices fall, underwriters buy shares on the open market, acting as buyers to support the price and protect investor interests.
Important Considerations
When evaluating offerings with overallotment options, be aware that while this mechanism aids price stability, it can also affect supply dynamics and short-term trading patterns. Investors should understand the underlying obligations underwriters assume and how they might influence market behavior.
Additionally, overallotment is tied to the underwriting agreement terms and impacts A shares issuance and distribution strategies. Being informed about these factors can help you better navigate IPO investments and market volatility.
Final Words
Overallotment clauses provide essential price stability during share offerings by allowing underwriters to adjust supply post-IPO. When evaluating new offerings, check if a greenshoe option is included to better understand potential price support mechanisms.
Frequently Asked Questions
Overallotment, also called a greenshoe option, is a provision allowing underwriters to sell up to 15% more shares than initially planned during an IPO. This helps manage supply and demand to stabilize the stock price after the offering.
Underwriters use overallotment to stabilize the stock price post-offering by selling extra shares short during high demand and later covering them either by buying from the issuer or in the open market, helping reduce price volatility.
Underwriters initially sell more shares than planned, creating a short position. If the price rises, they exercise the option to buy shares from the issuer at the offering price. If the price falls, they buy shares in the market at a lower price to cover shorts and support the stock price.
For example, if a company issues 10 million shares at $10 each with a 15% greenshoe, underwriters can sell 11.5 million shares. If the price rises to $12, they buy 1.5 million shares from the issuer at $10 to cover shorts. If it falls to $8, they buy shares in the market at $8, profiting while stabilizing the price.
The overallotment clause helps issuers by preventing extreme price volatility during early trading, boosting investor confidence, and ensuring a smoother market debut for the new shares.
While overallotment is common in U.S. registered offerings, similar mechanisms exist globally, such as the over-allotment facility in the UK, usually limited to about 15% to balance flexibility and regulatory compliance.
By using overallotment, underwriters create a short position and later cover it either by exercising the option to buy shares from the issuer or purchasing shares in the open market, allowing them to hedge without risking their own capital.


