First Horizon National Corp. (FHN) posted a first-quarter profit of $40 million, or 15 cents per share, on revenue of $370 million Thursday. During the period, the bank continued to benefit from improved credit quality and solid performances from regional bank First Tennessee and financial services provider FTN Financial. That first-quarter profit compares to a net loss of $27.6 million, or 12 cents per share, on revenue of $423.6 million a year earlier. The quality of loans under the lender’s roof continued to improve, resulting in the bank lowering its allowance for loan losses by 30% over the previous year. In the first quarter, First Horizon booked $589.1 million in allowance for loan losses down from $844 million a year ago. In addition, the provision for loan losses for the first quarter declined to $1 million from $45 million in the fourth quarter and $105 million last year. Meanwhile, net charge-offs  — or the gross amount of loans written off as bad debt — fell 58% from last year, with the bank recording $76 million in charge-offs for the first quarter down from $182 million a year earlier. Write to Kerri Panchuk.