One of Britain's biggest companies is warning its employees against a Brexit
The memo will be sent in conjunction with the CWU and Prospect worker unions, whose members make up a portion of BT's 81,400 staff.
Sky says that BT is keen to urge staff they can vote how they like, but that they should be aware of the risks a Brexit poses to the economy and all the companies operating in it.
Employees will also be reminded that the majority of businesses are for Remain, and that goods will be more expensive thanks to the falling Pound.
The memo concludes by stating that 20% of BT's business is outside the UK and that the EU has helped maintain beneficial employment laws.
Signatories include BT chairman Sir Michael Rake, who earlier this year also signed a letter in the Times from a number of the UK's biggest firms warning against a Brexit.
Since then many more companies have also campaigned for Remain. Earlier this month low-budget airline Ryanair went so far as to spam its customers with Remain emails, saying it was "absolutely clear" that the UK's growth prospects were stronger in the EU.
However on Saturday James Dyson - one of Britain's most successful entrepreneurs - came out in favour of a Brexit, saying that Britain "would gain more from leaving the EU than it would lose."
Polls for the referendum still suggest the vote is too close to call.
The most recent YouGov poll indicated that "Outers" have gained a slight edge, with 42% for Remain and 43% for Leave. Respondents in the poll said they disliked the Remain camp's "scaremongering" and "dishonesty."
But the referendum is already having an economic impact - the pound and euro fell to their lowest values since 2013, with analysts blaming the uncertainty of the outcome.