outsourcing of our transfer agency transactional processing operations, lower costs from reduced headcount and lower share-based compensation due to previously-issued awards vesting fully, as well as forfeitures. These decreases were partially offset by mark-to-market adjustments on deferred compensation plans.
General and administrative expenses for the third quarter of 2020 increased $2.5 million, or 15%, compared to the third quarter of 2019. For the nine months ended September 30, 2020, general and administrative expenses increased $10.9 million, or 23%, compared to the nine months ended September 30, 2019. For both comparative periods, the increases were primarily due to the shift of our transfer agency transactional processing operations outsourcing costs from technology expenses to general and administrative expenses and increased strategic project spending, partially offset by lower travel and meeting costs due to restricted travel and a transition to virtual meetings during the pandemic.
Technology expense for the third quarter of 2020 decreased $0.8 million, or 5%, compared to the same period of 2019. For the nine months ended September 30, 2020, technology expense decreased $5.8 million, or 12%, compared to the nine months ended September 30, 2019. For both comparative periods, the decreases were primarily due to costs related to the transfer agency transactional processing operations outsourcing shifting to general and administrative expenses, partially offset by increased consulting and software costs for new technologies.
Occupancy expense decreased $1.5 million, or 27%, for the third quarter of 2020 compared to the third quarter of 2019 and decreased $5.9 million, or 31%, for the nine months ended September 30, 2020, as compared to the same period in 2019. For both comparative periods, the decreases are due to the planned transition of field offices from corporate-leased space to Advisor personal branch offices.
Marketing and advertising expense decreased $0.8 million, or 36%, for the third quarter of 2020 compared to the third quarter of 2019 and decreased $2.1 million, or 33%, for the nine months ended September 30, 2020, as compared to the same period in 2019. For both comparative periods, the decreases are primarily due to lower sponsorship fees in connection with the shift to virtual industry conferences.
Depreciation expense decreased $1.8 million, or 38%, for the third quarter of 2020 compared to the third quarter of 2019 and decreased $6.3 million, or 39%, for the nine months ended September 30, 2020, as compared to the same period in 2019. The decreases were primarily due to capitalized software development assets becoming fully depreciated.
Investment and Other Income
Investment and other income for the three months ended September 30, 2020 increased 5%, compared to the same period in 2019 primarily due to greater unrealized gains, net of hedging activity, on the seed and corporate investment portfolios in the current period compared to the prior year comparative period, partially offset by a decline in interest income due to lower interest rates and redemptions in our corporate laddered investment portfolio and Pension Plan settlement expenses. For the nine months ended September 30, 2020, investment and other income decreased $10.8 million compared to the same period in 2019 primarily due to lower unrealized gains, net of hedging activity, on the seed and corporate investment portfolios, a decline in interest income and Pension Plan settlement expenses in the current period compared to the prior year comparative period.
Taxes
The following table reconciles the statutory federal income tax rate with our effective income tax rate from continuing operations for the three and nine months ended September 30, 2020 and 2019:
| | | | | | | | | | |
| | Three months ended | | | Nine months ended | |
| | September 30, | | | September 30, | |
| | 2020 | | 2019 | | | 2020 | | 2019 | |
Statutory federal income tax rate | | 21.0 | % | 21.0 | % | | 21.0 | % | 21.0 | % |
State income taxes, net of federal tax benefit | | 3.7 | | 2.7 | | | 3.6 | | 2.8 | |
Permanent differences | | 1.2 | | 0.6 | | | 1.3 | | 0.5 | |
Share-based compensation | | (0.5) | | (0.5) | | | 1.4 | | 1.6 | |
Other items | | (0.6) | | (0.5) | | | (0.4) | | (0.1) | |
Effective income tax rate | | 24.8 | % | 23.3 | % | | 26.9 | % | 25.8 | % |