Q21. I have marked my sell orders wrongly and the orders have been executed. Can I modify the order later? Will I be penalized if I do not correct the sell order?

Yes, you can approach your broker to correct your sell orders if the orders have been executed.  Your broker should submit the amendments to SGX on your behalf before 5.45pm on the next trading day.  You must inform your broker in advance so that he has sufficient time to prepare the amendments for submission to SGX.  You are also expected to accurately correct the quantity of the sell orders.

The accurate disclosure of sell orders is necessary for factual information to be provided to market participants regarding short selling.    As such information may be taken into account by investors when making trading decisions, it is important that false or misleading information not be presented.

Section 330(1) of the SFA states that any person who, with intent to deceive, makes or furnishes, or knowingly and wilfully authorises or permits the making or furnishing of, any false or misleading statement or report to a securities exchange, futures exchange, designated clearing house or any officers thereof relating to dealing in securities shall be guilty of an offence and shall be liable on conviction to a fine not exceeding $50,000 or to imprisonment for a term not exceeding 2 years or  both.  

In applying section 330(1) of the SFA, MAS will consider whether there was intent to deceive in respect of sell orders that had been inaccurately marked by SGX-ST Trading Members or inaccurately disclosed by market participants. As such, if you or your broker is found to have intent to deceive in respect of sell orders, you or your broker will be penalized under section 330(1).

Notwithstanding, as mentioned above, you may notify your broker to correct your sell orders and brokers are required to submit the amendments to SGX before 5.45pm the next trading day.

http://www.sgx.com/wps/portal/sgxweb/home/faqs#Marking_of_SellOrders