Preventing Unemployment Act of 2010

Preventing Unemployment Act of 2010 - Amends the Federal Unemployment Tax Act (FUTA), the Internal Revenue Code, and the Unemployment Compensation Amendments of 1992 to prescribe requirements for the treatment and temporary financing of voluntary short-time compensation (STC) programs, under which: (1) an employer reduces the number of hours worked by employees in lieu of temporary layoffs; and (2) such employees are eligible for pro-rata unemployment compensation if their workweeks are reduced by between 10% and an appropriate state-determined percentage.

Requires payments to states meeting the requirements of this Act in an amount equal to 100% of the STC paid to individuals.

Prohibits such STC payments: (1) for more than 26 weeks; or (2) for an employee whose employer's workforce during the three months preceding submission of the employer's STC plan has been reduced by temporary layoffs of more than 20%, or on a seasonal, temporary, or intermittent basis.

Authorizes temporary federal-state agreements for STC programs if a state does not currently provide for STC payments under an existing program.

Requires employers under an STC plan to pay the state one-half of the amount of STC paid under the plan.

Requires federal payments to states in an amount equal to: (1) one-half of the amount of STC paid to individuals by the state; and (2) any additional related administrative expenses incurred by the state.

Requires the Secretary of Labor to award one start-up grant to state agencies: (1) in states that enact STC programs on or after May 1, 2010; and (2) that apply for such grants before FY2013.

Specifies assistance and guidance the Secretary shall give states in establishing and implementing STC programs.