Note 14. Stock-Based Compensation

The Company rolled forward certain vested options from the Predecessor (see discussion below) to 2,783,479 equivalent vested options in the Company. No incremental compensation costs were recognized on conversion as the fair value of the options issued were equivalent to the fair value of the vested options of the Predecessor. Exercise prices for those options range from $0.87 to $6.09.

During 2019, pursuant to the Concrete Pumping Holdings, Inc. 2018 Omnibus Incentive Plan, the Company granted stock-based awards to certain employees in the U.S. and U.K. All awards in the U.S. are participating restricted stock awards while awards granted to employees in the U.K. are stock options with exercise prices of $0.01. Regardless of where the awards were granted, the awards vested pursuant to one of the four following conditions:

On October 29, 2020 almost all of the then-outstanding stock awards were modified as follows:

As a result of the modifications, and in accordance with ASC 718, the Company updated the fair value of each modified award to be equal to the following:

The fair values for the above awards were calculated using a Monte Carlo simulation model and the updated fair value of the stock award is expensed over the new service period for the new award. As a result of the modifications, the Company recorded $5.9 million of compensation expense on day 1 of the modification as the requisite service period is zero. Outside of the unrecognized compensation expense for all other awards, no incremental costs are expected to be incurred in the future.

As of April 30, 2021, the Company has the following outstanding stock-based awards:

Included in the table below is a summary of unvested awards at April 30, 2021, including the location, type of award, shares outstanding, unrecognized compensation expense, and the date that expense will be recognized through. In addition, while the table below provides a date through which expense will be recognized on a straight-line basis for the remaining market-based stock awards, if at such time they vest earlier than the Monte Carlo simulation derived service period, expense recognition will be accelerated. The $6 Market/Time-Based shares noted below achieved the $6.00 market condition on March 29, 2021, which was a date that was earlier than the Monte Carlo simulation had originally estimated. As such, the remaining unrecognized expense for these awards will be accelerated over the new remaining requisite service period. In addition, the Company has broken out the market-based awards by vesting tranche to address the accelerated attribution applied to the awards.

Note: The $13/$16/$19 Market/Time Based shares noted above relate to the shares not exchanged in the October 29, 2020 modification discussed above.

Stock-based compensation expense for the three and six-month periods ended  April 30, 2021 was $3.3 million and $4.0 million and has been included in general and administrative expenses on the accompanying consolidated statement of income. Stock-based compensation expense for the three and six-month periods ended  April 30, 2020 was $1.4 million and $2.9 million, respectively.