See: KL-Singapore HSR project terminated after both countries fail to reach agreement and Malaysia to go it alone with HSR project, pay RM300m compensation to Singapore — source
The bilateral agreement was inked in 2016 after three years of negotiations. Both sides signed a supplemental agreement in May 2018 at Malaysia’s request to suspend the construction of the project. A second agreement was signed to extend the suspension to Dec 31, 2020. The minister added that Singapore had spent some $270 million on the HSR project so far, lower than the earlier estimate of about $300 million provided by previous transport minister Khaw Boon Wan in 2018.