Lloyds TSB has unveiled details of its £12.2bn takeover of Halifax-Bank of Scotland (HBOS).
Together the banks hold close to one-third of the UK's savings and mortgage market.
Lloyds confirmed jobs would be lost as a result, but played down claims that up to 40,000 staff faced the axe.
But HBOS staff and customers are worried about what a merger will mean. BBC News website readers have been emailing their concerns and sharing their experiences:
I have an HBOS current account and a quite substantial savings account. Understandably, I am extremely worried about the future of this bank and I am considering transferring my accounts. There must be thousands of HBOS customers with similar worries so it is good news that Lloyds TSB is currently in merger talks.
Michael Cheyne, Newcastle upon Tyne
I have been very worried this week about my pounds in HBOS and the rumours have led me to withdraw over £120,000, which are all my life savings. I have changed my pounds into dollars, because even though the dollar is weaker, I am happier to have my money in several US banks where I can keep a closer eye on it. I may well move it back to HBOS after this period of worry is over. I will now be splitting everything I have between at least four American banks to ensure safety of my assets if HBOS goes bust. Later, I will move everything back to the UK where I will need to open several accounts in various banks to give me more security and less worry.
Joe, New York, USA
I am a Halifax customer and to be honest this is not concerning me in the least. Quite frankly, if there is any danger of HBOS collapsing then the government would have to step in as they couldn't afford a second Northern Rock fiasco. Lloyds TSB stepping in to secure our financial future in these difficult times can only be a good thing for customers, because there is still the option for the government to help should things get any worse.
Richard Rainbow, Leicester
I am concerned mainly because I can see that in the cost cutting that is going to follow I may lose my job. For all those people who are running about withdrawing their savings from Halifax, if it is less than £35,000 leave it alone; it is guaranteed by the Financial Services Compensation Scheme. Let's all not start a run on yet another bank and then we can drive them to the point of collapse, just like Northern Rock.
As a member of HBOS staff, I feel sick. This is the worst day of my life so far. The FSA has confirmed we are in a safe position, why is the government then overlooking the obvious fact that there would then be a monopoly in the financial market place as well as a large number of staff potentially loosing their jobs. It is disgusting.
I work at HBOS, and at 9am this morning, I was extremely concerned that the bank might not see it through to the end of my shift. Hopefully even just talks of a merger should steady the ship instead of these wild fluctuations.
Keiron Fairfield, Dunfermline, Fife
I work for HBOS as a calculations analyst, and am too old to find another job on the market. I therefore hope this will give stability to my job, and stop people panicking. The danger is, the usual IT merger of duplicated systems leading to utter chaos in the future, when the "cost accountants" get their inept fingers on the merged giant and try to justify their bloated salaries. I could lose the job I love, if and when that happens
Philip Dobson, Bristol
I am an employee and shareholder with HBOS plc. I have lost money on paper from shares I have accumulated but as I don't need this money at present I am prepared to ride out the storm. The merger with Lloyds TSB will undoubtedly cause concerns however I am confident that I will be able to come through any personal changes to circumstances Let's be more positive!
Tony McCabe, Glasgow
I am a Halifax / HBOS shareholder and customer for many years and I am very comfortable with the services they offer. This deal may fix the immediate problems, however, it does not address the real issues. The average person wants to be able to take a loan for a house or save without exposure the predatory / greed driven activities which have created this crisis and have resulted in pressure on HBOS in recent days. Capitalism in this form does not work for the ordinary man in the street. This is probably naive but we need a mechanism to save and borrow in an environment away from the wheeler dealers, why should they use our money to make their profits at our risk? It's a morally corrupt practice.
Brian Kneller, Doncaster
It's outrageous that these bankers came to the small share holders for an investment only a few months ago and now want us to take another financial hit. They must have known the severity of the potential problem at that time and what they have done is verging on criminal! If I ran my business that way I would end up in jail - these fat cats get huge bonuses for taking risk beyond their means.
Alan Pickering, Scarborough