I work for a bank. Every month I get a list of 10,000 customers of the bank with the outstanding loan balance for each customer. I add them up and report the total outstanding balance every month. I have data for past 24 months.
I am asked to give a rough prediction of the next month's total outstanding balance. I am not a statistician, hence need some help. So far ,I have below ideas, can someone comment on pro/cons of each?
Compute the average monthly % growth over last 6 months on Total balance; Multiply current balance by % growth to predict next month balance
Do the same at an individual customer level, that gives us 10,000 predicted balances for next month. Add them up to get total balance
Are there any time series techniques I can use here?
Can I find the answer by some simulation techniques?