Treasury Secretary Jacob Lew said Thursday the deadline for Congress to increase the government's borrowing cap has been moved up to about Nov. 5.

That likely means the matter must be resolved before House Speaker John Boehner, R-Ohio, leaves Congress at the end of October.

Lew said that tax receipts have come in below estimates and payments into military retirement trust funds are higher than anticipated.

Increasing the government's borrowing limit above $18.1 trillion is needed to prevent a first-ever default on government obligations like interest payments and Social Security. The government has never failed to meet its obligations and a default would likely have severe effects on interest rates and the economy.

Since the limit was reset in March, Treasury has employed accounting maneuvers known as "extraordinary measures" to be able to continue to borrow. Those measures chiefly involve suspending payments into federal retirement funds.

"We now estimate that Treasury is likely to exhaust its extraordinary measures on or about Thursday, Nov. 5," Lew wrote top lawmakers. "At that point, we would be left to fund the government with only the cash we have on hand, which we currently forecast to be below $30 billion."

Congress last increased the debt limit in February 2014.

In 2011, Republicans used the need to increase the debt limit as leverage to force President Barack Obama to agree to spending cuts. But Obama has since refused to negotiate over the debt limit and last year's increase passed largely on the votes of House and Senate Democrats.