General and administrative expenses for the fourth quarter of 2021 were RMB72.5 million (US$11.4 million) [1], a 42.4% year-over-year increase. The increase was mainly attributable to the opening of 29 L&O hotels since the beginning of 2021, increased one-time consulting fees for capital markets advice and increased bad debts during 2021. Excluding the impact from newly-opened L&O hotels and one-time consulting fees, general and administrative expenses for the fourth quarter of 2021 increased by 19.9%. General and administrative expenses for the full year 2021 were RMB268.3 million (US$42.1 million) [1], a 55.5% year-over-year decrease.
Gross profit for the fourth quarter of 2021 was RMB115.5 million (US$18.1 million) [1], a year-over-year decrease of 39.2%. Gross margin for the fourth quarter of 2021 was 37.6%, compared to 65.6% a year ago. The decrease was primarily due to the operating loss recorded by newly-opened L&O hotels during their ramp-up period. Gross profit for the full year 2021 was RMB554.8 million (US$87.1 million) [1], a 3.2% year-over-year increase.
Income from operations for the fourth quarter of 2021 was RMB36.1 million (US$5.7 million) [1], a year-over-year decrease of 69.5%, with a margin of 11.8%. The decrease was mainly due to the operating loss recorded by newly-opened L&O hotels during their ramp-up period. Income from operations for the full year 2021 was RMB241.7 million (US$37.9 million) [1], a year-over-year decrease of 24.3%.
Net income for the fourth quarter of 2021 was RMB28.6 million (US$4.5 million) [1], compared to RMB79.5 million in the fourth quarter of 2020 and net margin was 9.3%. The year-over-year decrease was mainly attributable to the operating loss recorded by newly-opened L&O hotels during their ramp-up period. Net income for the full year 2021 was RMB207.8 million (US$32.6 million) [1], a year-over-year decrease of 15.1%.
Adjusted EBITDA (non-GAAP) [2] for the fourth quarter of 2021 was RMB68.8 million (US$10.8 million) [1], a year-over-year decrease of 47.4%. Adjusted EBITDA margin, defined as adjusted EBITDA (non-GAAP) as a percentage of total revenues, for the fourth quarter of 2021 was 22.4%, compared to 45.1% a year ago. Excluding the impact of newly-opened hotels, adjusted EBITDA (non-GAAP) for the fourth quarter of 2021 was RMB105.0 million, with a margin of 40.2%. Adjusted EBITDA (non-GAAP) for the full year 2021 was RMB317.7 million (US$49.9 million) [1], a year-over-year decrease of 10.6%.
Core net income (non-GAAP) for the fourth quarter of 2021 was RMB35.9 million (US$5.6 million) [1], a year-over-year decrease of 67.2%. The core net margin, defined as core net income (non-GAAP) as a percentage of total revenues, for the fourth quarter of 2021 was 11.7%, compared to 37.7% one year ago. Core net income (non-GAAP) for the full year 2021 was RMB204.3 million (US$32.1 million) [1], a year-over-year decrease of 29.4%.
Earnings per ADS (basic and diluted) for the fourth quarter of 2021 were RMB0.25 (US$0.04) [1], down from RMB0.83 one year ago. Core net income per ADS (basic and diluted) (non-GAAP) for the fourth quarter of 2021 was RMB0.35 (US$0.05) [1], down from RMB1.06 a year ago. Earnings per ADS (basic and diluted) for the full year 2021 was RMB2.05 (US$0.32) [1] down from RMB2.54 one year ago. Core net income per ADS (basic and diluted) (non-GAAP) was RMB1.98 (US$0.31) [1] for the full year 2021, a decrease from RMB2.81 a year ago.
Cash flow Operating cash inflow for the fourth quarter of 2021 was RMB201.3 million (US$31.6 million) [1] as a result of income from operations. Investing cash outflow for the fourth quarter of 2021 was RMB256.4 million (US$40.2 million) [1], which was primarily attributable to purchases of short-term investment, investments and deposits for property and equipment, and loans to franchisees. The investing cash outflow was partially offset by proceeds from short-term investments. Financing cash inflow for the fourth quarter of 2021 was RMB154.2 million (US$24.2 million), mainly attributable to dividends distributed by the end of the year 2021. Operating cash inflow for the full year 2021 was RMB361.0 million (US$56.6 million) [1]. Investing cash outflow for the full year 2021 was RMB928.4 million (US$145.7 million) [1]. Financing cash inflow for the full year 2021 was RMB255.6 million (US$40.1 million) [1].
Cash and cash equivalents, restricted cash, short-term investments, investments in equity securities and time deposit. As of December 31 , 2021, the Company had total cash and cash equivalents, restricted cash, short term investments, investments in equity securities and time deposits of RMB1,235.9 million (US$193.9 million) [1], compared to RMB1,192.1 million as of September 30, 2021. The increase from the prior quarter was primarily attributable to cash from operating activities and drawing down of bank facilities but offset by dividend distribution to our shareholders, acquisition costs of our L&O hotels and changes in fair value of equity securities.
COVID-19 Update
Despite the resurgence of COVID-19 in the fourth quarter of 2021, we delivered solid results, with RevPAR recovering to 91.3% of its level in the same period in 2019. At the end of December 2021, our RevPAR had bounced back to almost 100% of its level in the fourth quarter of 2019 (the “4Q2019 Level”). With the resurgence of COVID-19 nationwide, our RevPAR fell to around 81.3% of the 4Q2019 Level in the first week of November 2021, but gradually recovered to 98.5% of the 4Q2019 Level in the last week of