* Dow member United Tech rises after upbeat results
* Twitter soars in heavy trading after Q1 revenue beats est
* Lockheed Martin jump after raising 2019 profit forecast
* Futures up: Dow 0.17%, S&P 0.04%, Nasdaq 0.06% (Changes analyst's comment, updates prices)
By Sruthi Shankar
April 23 (Reuters) - U.S. stocks were set to open slightly higher on Tuesday, as better-than-expected results from Coca-Cola, Twitter and a handful of industrial companies supported investor sentiment amid concerns about slowing profits.
Stock markets across the globe were subdued as European markets reopened after a four-day Easter break only to be helped by rising energy shares as oil prices rose to near six-month highs.
About a third of the S&P 500 companies including Boeing Co and Facebook Inc are scheduled to report this week, the busiest period of the reporting season.
With Wall Street's main indexes struggling to make headway, even as they hover below record levels, investors are waiting to see if results from major companies ease concerns about earnings recession.
Profits at S&P 500 companies are expected to decline 1.7% in the first quarter, in what could be the first earnings contraction since 2016. However, forecasts have improved slightly since the start of April.
"Nobody is quite sure what the earnings are going to look like and a lot of analysts have lowered expectations," said Mark Grant, chief global strategist at B. Riley FBR Inc.
"So we may get some kind of a pop as people realize that things aren't quite as bad as they feared."
Trading volume has been at its lowest so far in 2019.
At 8:45 a.m. ET, Dow e-minis were up 44 points, or 0.17%. S&P 500 e-minis were up 1.25 points, or 0.04% and Nasdaq 100 e-minis were up 4.5 points, or 0.06%.
Among the major names that have reported, Coca-Cola Co was up 2.7% in premarket trading after its quarterly sales beat analysts' estimates, while Twitter Inc gained 6.9% after the social media company posted better-than-expected quarterly revenue and a surprise rise in monthly active users.
Aerospace supplier United Technologies Corp gained 3% after reporting a higher-than-expected quarterly profit.
Lockheed Martin Corp's shares jumped 4.9% after the U.S. Pentagon's top weapons supplier reported a 47% jump in quarterly profit and raised its profit forecast for the year.
A decliner was Procter & Gamble, whose shares fell 1.8% after its quarterly EBIT margin missed estimates, despite reporting better-than-expected quarterly revenue and profit.
Economic data due at 10:00 a.m. ET is expected to show sales of new U.S. single-family homes dropped to a seasonally adjusted annual rate of 650,000 units in March, from 667,000 units in February. (Reporting by Sruthi Shankar and Amy Caren Daniel in Bengaluru; Editing by Shounak Dasgupta and Anil D'Silva)