Bernie Blegen
Vice President & Chief Financial Officer at Monolithic Power Systems
Thanks, Jen. MPS' first quarter revenue of $451.1 million came in about as expected; 19.4% higher than our first quarter of 2022 or 1.9% lower than the revenue reported in fourth quarter of 2022. Our results for the quarter were mixed with weaker quarter-to-quarter demand in our enterprise data and industrial markets, overshadowing improvements in consumer and automotive.
Let's take a quick look at our first quarter 2023 revenue by markets. First quarter 2023 consumer revenue of $63.4 million increased 19.5% from the fourth quarter of 2022. First quarter 2023 revenue was down 20.8% year-over-year. Consumer revenue represented 14.8% of first quarter 2023 revenue compared with a 21.2% contribution in the first quarter of 2022. First quarter 2023 automotive revenue of $105.3 million increased $8.0 million or 8.2% from the fourth quarter of 2022. The sequential revenues increased primarily due to continued acceptance of our highly integrated solutions for advanced driver assistance systems, digital cockpit and lighting applications. First quarter 2023 revenue was up 93.1% year-over-year. Automotive revenue represents 23.3% on MPS' first quarter 2023 revenue compared with 14.4% in our first quarter of 2022.
First quarter 2023 Communications revenue of $67.9 million rose $3.6 million or 5.6% from the fourth quarter of 2022. These quarter-over-quarter increases primarily reflected modest revenue improvements in the 5G infrastructure. First quarter 2023 revenue was up 22.2% year-over-year. Communications revenues represented 15.1% of MPS' first quarter 2023 revenue compared with 14.7% in the first quarter of 2022. In our Storage and Computing market, first quarter 2023 revenues of $119.8 million was essentially flat with revenue recorded in the fourth quarter of 2022, as declining storage revenue was offset by higher notebook sales. First quarter 2023 revenue was up 24.1% year-over-year. Storage and computing revenue represented 26.6% MPS' first quarter 2023 revenue compared with 25.6% in first quarter of 2022.
First quarter 2023 Industrial revenue of $47.5 million decreased $8.6 million or 15.3% from the fourth quarter of 2022. This quarter-over-quarter decrease was due to lower security and power source revenue. First quarter 2023 Industrial revenue was down 2.2% year-over-year. Industrial revenue represented 10.5% of our first quarter 2023 revenue compared with 12.9% in the first quarter of 2022. In Enterprise Data, the first quarter 2023 revenues of $47.2 million decreased $21.3 million or 31.1% from our fourth quarter 2022 due to broadbased weakness in data center spendings. First quarter 2023 revenue was up 10.9% year-over-year. Enterprise data revenue represented 10.5% of MPS first quarter 2023 revenues compared with 11.2% in first quarter of 2022.
I'd like to share some general business observations. During our most recent earnings calls, we highlighted that customers were becoming more concerned with near-term business conditions and that ordering patterns might oscillate; this behavior continued through first quarter of 2023. However, we do see order acceleration for products related to artificial intelligence, autonomous driving and power modules and our customer engagement and design win momentum remains strong across all our markets. Regarding operating expenses, we continue to invest in our operations to support long-term growth. In response to customer concerns, we are expanding and geographically diversifying our global production, operations and our R&D activities.
In summary, we have strong customer engagement, design win momentum and are continuing to invest for the long term, even though timing of the revenue ramp from our customers remains uncertain.
Moving now to few comments on gross margins; GAAP gross margin was 57.4% and 80 basis points lower than fourth quarter of 2022 and 60 basis points lower than first quarter of 2022. Our GAAP operating income was $124.3 million compared with $136.9 million reported in the fourth quarter of 2022. For the first quarter of 2023, non-GAAP gross margin was 57.7%, 80 basis points lower than the fourth quarter of 2022 and 60 basis points lower than in the first quarter of 2022. This downward pressure on gross margin is expected to continue near term as we work through higher value inventory built during the supply-demand balance following the pandemic. Our non-GAAP operating income was $164.1 million compared to $174.1 million reported in the fourth quarter of 2022.
Let's review our operating expenses. Our GAAP operating expenses were $134.5 million in the first quarter of 2023 compared with $130.9 million in the fourth quarter of 2022. Our non-GAAP first quarter 2023 operating expenses was $96.0 million, up from $94.8 million reported in fourth quarter of 2022. The difference between GAAP and non-GAAP operating expense for the quarters discussed here are primarily stock compensation expenses and income or loss from an unfunded deferred compensation plans. For the first quarter of 2023, total stock compensation expense included approximately $1.1 million charge to cost of goods sold -- was $37.0 million compared to $35.3 million reported in the fourth quarter of 2022.
Switching to the bottom line; first quarter 2023 GAAP net income was $109.8 million or $2.26 per fully diluted share compared with $119.1 million or $2.45 per fully diluted share in the fourth quarter of 2022. First quarter 2023 non-GAAP net income was $146 million or $3.00 per fully diluted share compared with $154 million or $3.17 per fully diluted share in fourth quarter of 2022. Fully diluted shares outstanding at the end of Q1 2023 were 48.7 million.
Now, let's look at the balance sheet. Cash, cash equivalents and investments were $919.1 million at the end of the first quarter of 2023 compared to $739.6 million at end of the fourth quarter of 2022. For the quarter, MPS generated operating cash flows of $218.8 million compared with operating cash flow of $52.2 million in fourth quarter of 2022. First quarter 2023 capital spendings totaled $8.9 million. Accounts receivable ended the first quarter of 2023 at $184.3 million or 37 days of sales outstanding, up 1 day from 36 days at the end of the fourth quarter 2022. Our internal inventories at the end of the first quarter of 2023 were $430.8 million, down from $447.3 million at the end of the fourth quarter of 2022. Days of inventory decreased to 204 [Phonetic] days at the end of Q1 2023 compared with 212 days at the end of fourth quarter of 2022. Comparing current inventory levels with the following quarters projected revenue, you can see days of inventory decreased to 203 days at the end of first quarter of 2023 from 212 days at the end of the fourth quarter of 2022.
I would now like to turn to our outlook for the second quarter of 2023. We are forecasting Q2 revenue in ranges of $430 million to $450 million. We also expect the following; GAAP gross margin in the range of 55.9% to 56.5%, non-GAAP gross margin in the range of 56.2% to 56.8%, GAAP R&D and SG&A expenses between $132.5 million and $136.5 million, GAAP R&D and SG&A expenses to be in the ranges of $94.9 million to $96.9 million; this estimate excludes stock compensation expenses but includes litigation expenses.
Total stock-based compensation expense was $38.8 million to $40.8 million, including approximately $1.2 million that would be charged to cost of goods sold. Interest and other incomes expected to range from $3.8 million to $4.2 million before foreign exchange gains or losses and fully diluted shares to be in range of 48.6 million to 49.0 million shares. In conclusion, we remain cautious about near-term business conditions, MPS will continue to focus on business development and investing in infrastructure as necessary to support our long term growth.
I'll now open the webinar up for questions.