CNA's underlying combined ratio of 91.9% improved nearly 2 points over the prior year quarter of 93.7%, with a 1.6 percentage point improvement in the expense ratio.
Rate continues to be strong with an 11% increase in the quarter.
CNA's investment portfolio ended the quarter with $4.3 billion in unrealized gains, down from a high of $5.7 million last quarter, primarily due to higher interest rates.
Boardwalk's revenue increased to $370 million in the first quarter of 2021 that was due to growth projects that had been placed into service and the colder winter weather.
By the end of the first quarter of '21, 23 of the company's 27 hotels were open.
The average daily room rate of our owned and JV hotels that are open increased by 25% to $234.
Loews Hotels has an ownership interest in nearly 15,000 rooms, approximately 11,000 of which are located in resort destinations.
Loews acquired Altium in 2017 for $1.2 billion; that was $600 million in equity and $600 million in debt at the Altium level.
In February of 2021, Altium refinanced its term loans and replaced its roughly $850 million of debt with a new $1.05 billion seven-year term loan, allowing the company to pay $200 million dividend to Loews.
And a month later, on April 1, Loews sold 47% stake in Altium to GIC, the Singapore wealth fund, for gross cash proceeds of $422 million.
With these two transactions, Loews has recouped its entire initial investment in Altium while still retaining a 53% ownership interest in the company.
Finally, so far in 2021 Loews has purchased more than 6,150,000 shares of our common stock at an average price of $49.58 per share for a total of $305 million, representing 2.3% of our outstanding shares.
For the first quarter, Loews reported net income of $261 million or $0.97 per share, a sharp rebound from last year's first quarter net loss of $632 million or $2.20 per share.
CNA contributed net income of $279 million, up dramatically from a $55 million net loss in Q1 2020.
Net earned premium was up almost 6% year-over-year, and the combined ratio, excluding cat losses, was 91.3%, 1.7 points better than last year's first quarter and 1.1 points better than full year 2020.
The loss ratio, excluding cats, was 59.5%, an excellent result that was in line with last year's first quarter and with full year 2020.
I would note that prior-year development was comparable this year and last, with less than 1 point of favorable development in both periods.
CNA's expense ratio, which, together with the loss ratio, makes up the combined ratio, declined to 31.5%, which was 1.6 points better than in Q1 2020.
As an historical footnote, the Company's expense ratio in, say, 2017, was over 34%, so you can see how far CNA has come in a few short years.
CNA booked 6.8 points of cat losses in Q1, up from 4.3 points in last year's first quarter.
As a result, the Company's overall combined ratio was up slightly to 98.1% from 97.3% last year.
CNA's after-tax net investment income increased $133 million or 48% from last year, with common stocks and limited partnership investments accounting for the entire improvement.
The S&P 500 returned 6.2% in this year's first quarter as compared to a negative 19.6% total return in Q1 of last year.
The turnaround in CNA's net investment gains were substantial, swinging from net pre-tax investment losses of $216 million in Q1 '20 to investment gains of $57 million in Q1 '21.
Taken together, the uplift in CNA's net investment income and the turnaround in its net investment gains benefited Loews' year-over-year net income by $306 million.
Boardwalk posted an over 8% increase in net revenue and a net income contribution of $85 million, up from $65 million in last year's first quarter.
The company posted a net loss of $43 million in the quarter versus a net loss of $25 million in Q1 '20.
GAAP operating revenue was $39 million, down from $109 million last year, and the pre-tax equity loss from joint venture properties was $12 million as opposed to a $4 million loss last year.
Adjusted EBITDA was $61 million in Q1 of 2019 and declined to $17 million in Q1 of 2020 and was a loss of $13 million in this year's first quarter.
The low point for profitability was last year's second quarter when Loews Hotels posted an adjusted EBITDA loss of $54 million.
For a good snapshot of this operational improvement, I would encourage you to review page 11 of our quarterly earnings supplement, which shows the increase in available rooms, occupancy and average daily rate since Q2 last year.
We currently expect, absent any divestitures or development projects, to make a net cash contribution to Loews Hotels of less than $80 million in 2021, down materially from our earlier estimates, given better-than-anticipated cash flow.
During the first quarter, we invested $32 million in Loews Hotels.
The parent company's investment portfolio generated net pre-tax income of $46 million as compared to a loss of $166 million last year.
The remainder of the corporate sector generated a $75 million pre-tax and $106 million after-tax loss in the quarter.
One, Altium undertook a recapitalization during the quarter, refinancing its existing term loans with a single $1.05 billion term loan; the company booked a $14 million pre-tax debt extinguishment charge in connection with the recap.
And second, the sale of a 47% stake in Altium to GIC, which was pending at quarter-end, required Loews to book a $35 million deferred tax liability which impacted net income but not pre-tax income.
Diamond Offshore materially affected our year-over-year earnings comparison, given Diamond's $452 million net loss in last year's first quarter, driven largely by rig impairments.
During the quarter, we repurchased 5.6 million shares of our common stock for $274 million, and we received about $274 million in dividends from CNA in the quarter, including the $0.38 regular quarterly dividend and the $0.75 special dividend.
We also received, as Jim mentioned, $199 million dividend from Altium pursuant to its recapitalization.
The parent company portfolio of cash and investments stood at $3.6 billion at quarter-end, with about 80% in cash and equivalents.
After quarter-end, we received about $410 million in net proceeds from the sale of 47% of Altium and have repurchased another 599,000 shares of common stock for about $32 million.
The transaction price implied a total enterprise value of $2 billion for the company and a total equity value of about $900 million.
As a reminder, we purchased the company for a total enterprise value of $1.2 billion in 2017 and have not invested any additional capital in Altium since the acquisition.
In the second quarter, upon deconsolidation, we will book a net pre-tax gain of approximately $560 million, which reflects both the net realized gain on the stake sold to GIC and the unrealized gain on our retained 53% stake.
The 53% stake will be held as an equity investment in a non-consolidated subsidiary at approximately $475 million, reflecting the valuation implied by the price paid by GIC for its 47% stake.

Summary:
For the first quarter, Loews reported net income of $261 million or $0.97 per share, a sharp rebound from last year's first quarter net loss of $632 million or $2.20 per share.