Yesterday, we reported first quarter operating earnings of $0.87 per share.
We achieved percent top line growth or 10% growth when adjusting the comparable quarter last year for premium returned to transportation insurers.
As a reminder, at the onset of the pandemic, we helped our public auto insurers by adjusting or returning premium, which resulted in a $23 million decrease in our transportation business.
In total, we posted a 86.9 combined ratio.
Investment income was down 7.6%, reflective of the decline in reinvestment rates during 2020.
Property led the way, up 31% as rates and market disruption continue to support growth.
Reported casualty growth was plus 19% compared to last year.
But as previously mentioned, we want to call out the comparative benefit from the $23 million public auto premium adjustment in the first quarter of last year.
From an underwriting perspective, this quarter's combined ratio of 86.9 compared to 92.0 a year ago.
Our loss ratio declined 5.6 points to 45.9 points despite a 7 point impact from winter storm, Uri, one of our largest winter or spring storm events experienced.
Of the $16 million in net storm loss, $15 million was in the property segment and $1 million was in the casualty segment related to the property exposure in certain packaged coverages.
In the first quarter of 2020, we recorded $5 million in COVID specific reserves, $2 million of property, and $3 million in casualty.
The casualty segment is influenced in this result and its underlying loss ratio was down about 3 points from the same period last year.
Our quarterly expense ratio increased 0.5 point to 41 [Phonetic].
In addition, general corporate expense was up $1.6 million.
All in, our portfolio posted a 0.2% return for the first quarter and we are more than happy to trade a modest price decline in bonds for the opportunity to put operating cash flow to work at higher rates.
Outside of the core portfolio, investee earnings were also a contributor in the quarter with Maui Jim and Prime each adding $3.7 million to the quarter's results.
As Todd mentioned, we're off to a running start to the year, reporting 87 combined ratio and 10% underlying growth in gross written premium.
The sub-90 combined ratio we achieved is a testament to our well-diversified portfolio of specialty products and the consistency of our disciplined underwriting approach.
In casualty, we report an outstanding 83 combined ratio and grew gross premiums 19%, 4% adjusted for transportation.
We were still able to achieve 8% rate increase in this segment overall, while account retentions are holding well.
Property segments top line grew 31% on a small underwriting loss as a result of the widespread winter storm, Uri.
We achieved 10% rate for the segment overall.
Emissions continue to increase significantly and we experienced top line growth of more than 25% on a very good underwriting results.
In surety, we grew top line 5% and achieved a 79 combined ratio.

Summary:
From an underwriting perspective, this quarter's combined ratio of 86.9 compared to 92.0 a year ago.
In the first quarter of 2020, we recorded $5 million in COVID specific reserves, $2 million of property, and $3 million in casualty.