In our efforts to continue to enhance shareholder value, Prosperity repurchased 2,092,000 shares of its common stock at an average weighted price of $52.59 per share during the first quarter of 2020.
The net income was $130 million for the three months ended March 31, 2020, compared with $82 million for the same period in 2019.
Our earnings per diluted common share were $1.39 for the three months ended March 31, 2020, compared with $1.18 for the same period in 2019, a 17.8% increase.
For the first quarter of 2020, on an annualized basis, return on average assets was 1.67%, return on average common equity was 8.86% and return on average tangible common equity was 20.1%.
Prosperity's efficiency ratio, excluding net gains on the sale of assets and taxes, was 42.9% for the three months ended March 31, 2020.
Our loans at March 31, 2020, were $19.1 billion, an increase of $8.7 billion or 83.7% compared with the $10.4 billion at March 31, 2019.
Linked quarter loans increased $281 million, 1.5% or 6% annualized compared with the $18.8 billion at December 31, 2019.
Our deposits at March 31, 2020, were $23.8 billion, an increase of $6.6 billion or 38.5% compared with the $17.1 billion at March 31, 2019.
Our linked quarter deposits decreased $373 million or 1.5% from the $24.2 billion at December 31, 2019.
Excluding deposits we assumed in the merger and new deposits we generated at the acquired banking centers since November 1, 2019, deposits at March 31, 2020, grew $1 billion or 6% compared with March 31, 2019, and grew $162 million, nine basis points, or 3.6% compared annualized with December 31, 2019.
Our nonperforming assets totaled $67 million or 25 basis points of quarterly average interest-earning assets at March 31, 2020, compared with $40 million or 21 basis points of quarterly average interest-earning assets at March 31, 2019, and $62 million or 25 basis points of quarterly average interest-earning assets at December 31, 2019.
During the first quarter of 2020, Prosperity increased its allowance for credit losses to $327 million from $87 million in the fourth quarter of 2019 after adopting accounting standard ASU 2016-13, also known as CECL.
Our allowance for credit losses to total loans excluding the warehouse purchase program loans, now stands at 1.88% compared with 51 basis points at December 31, 2019.
Net interest income before provision for credit losses for the three months ended March 31, 2020, was $256 million compared to $154.9 million for the same period in 2019, an increase of $101.1 million or 65.3%.
The increase was primarily due to the merger with LegacyTexas in November 2019 and $28.5 million in loan discount accretion in the first quarter of 2020.
The net interest margin on a tax equivalent basis was 3.81% for the three months ended March 31, 2020, compared to 3.2% for the same period in 2019 and 3.66% for the quarter ended December 31, 2019.
Excluding purchase accounting adjustments, the core net interest margin for the quarter ended March 31, 2020, was 3.36% compared to 3.16% for the same period in 2019 and 3.26% for the quarter ended December 31, 2019.
Noninterest income was $34.4 million for the three months ended March 31, 2020, compared to $28.1 million for the same period in 2019.
Noninterest expense for the three months ended March 31, 2020, was $124.7 million compared to $78.6 million for the same period in 2019.
For the second quarter 2020, we expect normalized noninterest expense to range around $120 million to $125 million.
In addition to this, we expect $3 million to $5 million in onetime merger expenses related to upcoming June conversion.
To date, we have already realized some cost savings from the merger and eventually expect additional cost savings of approximately $8 million to $9 million per quarter.
Combined, this will be in line with announced 25% cost savings.
The efficiency ratio was 42.9% for the three months ended March 31, 2020, compared to 42.94% for the same period in 2019 and 58.07% for the three months ended December 31, 2019, which included $46.4 million in merger-related expenses.
The bond portfolio metrics at 3/31/2020, showed a weighted average life of 3.08 years and projected annual cash flows of approximately $2.2 billion.
Our nonperforming assets at quarter end March 31, 2020, totaled $67,179,000 or 35 basis points of loans and other real estate.
The March 31, 2020, nonperforming assets total was made up of $61,449,000 in loans, $278,000 in repossessed assets and $5,452,000 in other real estate.
Of the $67,179,000 in nonperforming assets, $13,187,000 or 20% are energy credits, $12,869,000 of which are service company credits and $318,000 are production company credits.
Net charge-offs for the three months ended March 31, 2020, were $801,000.
The average monthly new loan production for the quarter ended March 31, 2020, was $476 million.
Loans outstanding at March 31, 2020, were $19.127 billion.
The March 31, 2020, loan total is made up of 36% fixed rate loans, 36% floating rate loans and 28% that reset at specific intervals.

Summary:
Our earnings per diluted common share were $1.39 for the three months ended March 31, 2020, compared with $1.18 for the same period in 2019, a 17.8% increase.