We investigate how the length of the net operating loss carryback period affects corporate liquidity and marginal tax rates. We estimate that extending the carryback period from two to five years, as recently proposed in President Obama’s budget blueprint, would provide $19 ($34) billion of additional liquidity to the corporate sector for 2008 (2009). Our calculations imply that the benefits of the extended carryback period would be concentrated in the homebuilding, automobile, and financial industries. Extending the carryback period would increase the marginal tax rate of loss firms by more than 200 basis points on average, which all else equal would lead corporations to use an additional $8 ($10) billion of debt and reduce tax payments by another $1.2 ($1.5) billion in 2008 (2009). Overall, the tax break proposed by the Obama administration would have a significant liquidity effect on corporations suffering large losses in recent years. If the tax proposal were extended to include TARP firms, the liquidity effect would triple in size.