Ms. Bui Thi Thanh Thao (Da Nang), an accountant at the Regional Investment and Construction Project Management Board, has the following questions regarding the increase and decrease of contract security value in construction contracts: A construction contract was signed and became effective on September 7, 2023, with a contract value of 7 billion VND (the contract security also became effective on September 7, 2023, and its value is 3% of the contract value, i.e., 210 million VND, as stipulated in the contract). On September 1, 2025, the contract value increased by 3 billion VND, bringing the total contract value after adjustment to 10 billion VND. Ms. Thao requests that the company adjust the contract security value to reflect this increase of 3 billion VND. Therefore, according to Ms. Thao's proposal, after the contract value increases to 10 billion VND, the contract guarantee should be 3% * 10 billion VND, which is 300 million VND. The company disagreed with Ms. Thao's proposal, arguing that as of September 1, 2025, the company had already completed 3 billion VND of the old contract value, so it only needed to adjust the guarantee based on the remaining contract value of 4 billion VND plus the additional 3 billion VND, which is 3% of 7 billion VND (meaning the contract guarantee value would not change, only the contract value within the guarantee would change; the company would maintain the 210 million VND guarantee). However, Ms. Thao researched the regulations on contract guarantees and found that the guarantee level is 2%-11% of the contract value, and the guarantee is valid from the date of signing until the project is put into warranty. She also stated in her contract that it is 3% of the contract value. Ms. Thao argues that after the contract value increased to 10 billion VND, the contract guarantee should be 3% of 10 billion VND, or 300 million VND. Currently, the project is not yet completed and has not been put under warranty, so the initial contract guarantee is still valid. Ms. Thao requests clarification from the relevant authorities to facilitate her work. The Ministry of Construction responded to this issue as follows: The question does not specify the funding source or the contract signing date, therefore the Ministry of Construction does not have a basis to answer. If the contract you mentioned falls within the scope of Government Decree No. 37/2015/ND-CP dated April 22, 2015, detailing construction contracts, then: Clause 4, Article 16 of Decree No. 37/2015/ND-CP stipulates: "The value of the performance guarantee and the method of guarantee must be specified in the tender documents or request for proposals. The performance guarantee amount is determined within the range of 2% to 10% of the construction contract price; in cases to mitigate high risks, the performance guarantee value may be higher but not exceeding 30% of the contract price and must be approved by the competent authority for investment decisions." Clause 1, Article 37 of Government Decree No. 37/2015/ND-CP dated April 22, 2015 stipulates that "The parties to the contract must specifically agree on the cases in which the volume, scope, and procedures for adjusting the volume may be adjusted." Clause 3, Article 37 of Government Decree No. 37/2015/ND-CP dated April 22, 2015, as amended by Clause 13, Article 1 of Government Decree No. 50/2021/ND-CP, stipulates: "For additional volumes arising outside the scope of the signed contract that do not have provisions on unit prices or methods for determining unit prices in the contract, the parties to the contract must agree on and finalize the unit price or principles and methods for determining the price to perform this volume of work before execution."