* Apple to report after markets close on Tuesday
* Eyes on iPhone sales and forecasts
* Chipmakers point to slackening demand for premium phones
* For results preview, click
By Savio D'Souza and Ankur Banerjee
May 1 (Reuters) - Apple reports second-quarter results later on Tuesday, following warnings from some chipmakers who supply the world's biggest smartphone makers about demand for the iPhone and other top-end models.
Shares in the world's biggest publicly traded company have slid along with many others in the technology sector this year. Apple's 2.4 percent drop year-to-date in 2018 is its steepest since 2016, although in that year the company had already reported by the end of April.
The latest hit to the stock came in mid-April after a warning on global demand from Taiwan Semiconductor Manufacturing Co Ltd, the world's largest contract chipmaker, reminiscent of one from Cirrus Logic Inc five years ago.
Apple is estimated to have sold 53 million iPhones from January through March, a 4.4 percent increase year over year, according to financial data and analytics firm FactSet.
Total revenue is expected to have risen 15 percent to $60.84 billion, with net profit jumping 24 percent to $13.68 billion, or $2.68 per share, according to Thomson Reuters I/B/E/S.
However, the iPhone sales estimate is down 9.4 percent from three months back, amid reports of waning demand. The revenue estimate has fallen 7.4 percent and profit estimate by 3.8 percent.
Along with the estimates, its stock price has also slid this year, weakening the chances of Apple becoming the first company to top $1 trillion in value by market capitalization.
The stock has topped the $900-billion mark four times in 2018, including as recently as last week, before each time falling back.
Apple, hard to characterise as an out and out manufacturer or pure technology play, currently trades at 13.5 times its estimated earnings for the next twelve months, higher than its five-year average of close to 13. That is almost double the equivalent number for its main phone industry competitor, Samsung Electronics, but below U.S. tech peers Alphabet or Microsoft.
Reporting by Savio D'Souza and graphics by Ankur Banerjee in Bengaluru; editing by Patrick Graham