The project's estimated cost has increased from $3.5 billion when first proposed to $4.3 billion in 1999, $5.3 billion in 2003, $6.3 billion in 2004, $7.2 billion in 2008, $8.4 billion in 2012, and either $9.7 billion or $10.8 billion in 2014. By 2017, the projected cost was either $12 billion or $10.2 billion, making it the most expensive construction project of its type in the world by either measure. The MTA budgeted a total of $10.178 billion to the project over five 5-year capital programs, up to and including the 2015–2019 capital program. Of these, 27% are federal funds and the other 73% are local funds. , the MTA had spent $7.397 billion of the available funding. , the project was expected to cost $11.1 billion, an increase from a previous estimate of $10.2 billion. The project had $10.3 billion in funding, which allowed construction to continue through 2020. The state legislature had to approve an additional $798 million to allow construction to be completed, but this had not been approved by late 2019.